fetch blocks of vals in aggregation for all cardinality

[PSeitz]

• fetch blocks of vals in aggregation for all cardinality
• move caching in common accessor

 aggregation::agg_tests::bench::bench_aggregation_average_f64                       5,942,104        5,148,082             -794,022  -13.36%   x 1.15 
 aggregation::agg_tests::bench::bench_aggregation_average_f64_multi                 11,417,079       11,905,300             488,221    4.28%   x 0.96 
 aggregation::agg_tests::bench::bench_aggregation_average_f64_opt                   10,851,455       10,328,652            -522,803   -4.82%   x 1.05 
 aggregation::agg_tests::bench::bench_aggregation_average_u64                       5,738,694        5,132,859             -605,835  -10.56%   x 1.12 
 aggregation::agg_tests::bench::bench_aggregation_average_u64_and_f64               10,323,814       9,441,560             -882,254   -8.55%   x 1.09 
 aggregation::agg_tests::bench::bench_aggregation_average_u64_and_f64_multi         26,116,150       25,086,729          -1,029,421   -3.94%   x 1.04 
 aggregation::agg_tests::bench::bench_aggregation_average_u64_and_f64_opt           22,321,784       21,670,827            -650,957   -2.92%   x 1.03 
 aggregation::agg_tests::bench::bench_aggregation_average_u64_multi                 12,767,874       11,943,697            -824,177   -6.46%   x 1.07 
 aggregation::agg_tests::bench::bench_aggregation_average_u64_opt                   10,784,961       9,784,827           -1,000,134   -9.27%   x 1.10 
 aggregation::agg_tests::bench::bench_aggregation_avg_and_range_with_avg            20,777,644       21,730,091             952,447    4.58%   x 0.96 
 aggregation::agg_tests::bench::bench_aggregation_avg_and_range_with_avg_multi      41,094,900       38,388,767          -2,706,133   -6.59%   x 1.07 
 aggregation::agg_tests::bench::bench_aggregation_avg_and_range_with_avg_opt        31,187,511       33,683,952           2,496,441    8.00%   x 0.93 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only                    18,582,468       12,670,097          -5,912,371  -31.82%   x 1.47 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only_hard_bounds        14,368,286       8,467,926           -5,900,360  -41.07%   x 1.70 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only_hard_bounds_multi  19,800,917       14,194,739          -5,606,178  -28.31%   x 1.39 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only_hard_bounds_opt    17,114,142       12,168,552          -4,945,590  -28.90%   x 1.41 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only_multi              28,772,087       18,172,721         -10,599,366  -36.84%   x 1.58 
 aggregation::agg_tests::bench::bench_aggregation_histogram_only_opt                23,780,209       15,942,567          -7,837,642  -32.96%   x 1.49 
 aggregation::agg_tests::bench::bench_aggregation_histogram_with_avg                45,636,068       38,374,941          -7,261,127  -15.91%   x 1.19 
 aggregation::agg_tests::bench::bench_aggregation_histogram_with_avg_multi          66,135,585       62,101,487          -4,034,098   -6.10%   x 1.06 
 aggregation::agg_tests::bench::bench_aggregation_histogram_with_avg_opt            63,782,712       59,397,435          -4,385,277   -6.88%   x 1.07 
 aggregation::agg_tests::bench::bench_aggregation_range_only                        8,859,395        8,744,853             -114,542   -1.29%   x 1.01 
 aggregation::agg_tests::bench::bench_aggregation_range_only_multi                  18,561,760       14,729,939          -3,831,821  -20.64%   x 1.26 
 aggregation::agg_tests::bench::bench_aggregation_range_only_opt                    10,784,218       11,994,109           1,209,891   11.22%   x 0.90 
 aggregation::agg_tests::bench::bench_aggregation_range_with_avg                    17,530,600       15,944,098          -1,586,502   -9.05%   x 1.10 
 aggregation::agg_tests::bench::bench_aggregation_range_with_avg_multi              31,067,284       25,016,654          -6,050,630  -19.48%   x 1.24 
 aggregation::agg_tests::bench::bench_aggregation_range_with_avg_opt                24,251,764       24,028,501            -223,263   -0.92%   x 1.01 
 aggregation::agg_tests::bench::bench_aggregation_stats_f64                         5,597,841        4,815,704             -782,137  -13.97%   x 1.16 
 aggregation::agg_tests::bench::bench_aggregation_stats_f64_multi                   12,227,305       10,762,508          -1,464,797  -11.98%   x 1.14 
 aggregation::agg_tests::bench::bench_aggregation_stats_f64_opt                     10,552,396       9,358,999           -1,193,397  -11.31%   x 1.13 
 aggregation::agg_tests::bench::bench_aggregation_terms_few                         3,398,698        3,349,821              -48,877   -1.44%   x 1.01 
 aggregation::agg_tests::bench::bench_aggregation_terms_few_multi                   18,604,549       10,138,197          -8,466,352  -45.51%   x 1.84 
 aggregation::agg_tests::bench::bench_aggregation_terms_few_opt                     12,700,642       7,060,409           -5,640,233  -44.41%   x 1.80 
 aggregation::agg_tests::bench::bench_aggregation_terms_many2                       14,355,628       13,626,684            -728,944   -5.08%   x 1.05 
 aggregation::agg_tests::bench::bench_aggregation_terms_many2_multi                 40,380,602       19,984,981         -20,395,621  -50.51%   x 2.02 
 aggregation::agg_tests::bench::bench_aggregation_terms_many2_opt                   28,780,245       17,929,649         -10,850,596  -37.70%   x 1.61 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_order_by_term          15,770,133       15,161,564            -608,569   -3.86%   x 1.04 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_order_by_term_multi    35,212,879       22,290,228         -12,922,651  -36.70%   x 1.58 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_order_by_term_opt      31,339,182       18,947,793         -12,391,389  -39.54%   x 1.65 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_with_sub_agg           128,122,516      115,084,171        -13,038,345  -10.18%   x 1.11 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_with_sub_agg_multi     200,759,294      177,645,007        -23,114,287  -11.51%   x 1.13 
 aggregation::agg_tests::bench::bench_aggregation_terms_many_with_sub_agg_opt       181,130,229      162,938,489        -18,191,740  -10.04%   x 1.11