GMS type simplifications

[max-hoffman]

No description provided.

[max-hoffman]

#newbenchmark

[github-actions]

@max-hoffman workflow run: https://github.com/dolthub/dolt/actions/runs/2618534772

[github-actions]

@max-hoffman

read_tests	from_latency_median	to_latency_median	is_faster
covering_index_scan	6.79	6.67	0
groupby_scan	63.32	62.19	0
index_join_scan	33.72	33.72	0
index_scan	70.55	66.84	0
oltp_point_select	0.7	0.72	0
oltp_read_only	13.22	13.22	0
select_random_points	1.7	1.67	0
select_random_ranges	1.61	1.61	0
table_scan	65.65	56.84	1

write_tests	from_latency_median	to_latency_median	is_faster
bulk_insert	0.001	0.001	0
oltp_delete_insert	11.45	11.87	0
oltp_insert	3.36	3.43	0
oltp_read_write	21.5	21.89	0
oltp_update_index	5.09	5.37	0
oltp_update_non_index	5.37	5.77	0
oltp_write_only	9.73	9.91	0

[github-actions]

@max-hoffman

read_tests	from_latency_median	to_latency_median	is_faster
covering_index_scan	6.79	6.67	0
groupby_scan	63.32	62.19	0
index_join_scan	33.72	33.72	0
index_scan	70.55	68.05	0
oltp_point_select	0.7	0.72	0
oltp_read_only	13.22	13.22	0
select_random_points	1.67	1.67	0
select_random_ranges	1.61	1.61	0
table_scan	65.65	56.84	1

write_tests	from_latency_median	to_latency_median	is_faster
bulk_insert	0.001	0.001	0
oltp_delete_insert	10.84	10.84	0
oltp_insert	3.36	3.36	0
oltp_read_write	21.5	21.5	0
oltp_update_index	4.91	4.91	0
oltp_update_non_index	5.18	5.18	0
oltp_write_only	9.56	9.56	0