handle normal reads in validation sample in BasicSomaticValidator

[davidbenjamin]

@takutosato This is for MC3.

[takutosato]

Looks good!

[codecov-io]

Codecov Report

Merging #5322 into master will decrease coverage by 0.001%.
The diff coverage is 25%.

@@               Coverage Diff               @@
##              master     #5322       +/-   ##
===============================================
- Coverage     86.793%   86.792%   -0.001%     
  Complexity     30107     30107               
===============================================
  Files           1842      1842               
  Lines         139393    139395        +2     
  Branches       15369     15370        +1     
===============================================
  Hits          120984    120984               
- Misses         12823     12824        +1     
- Partials        5586      5587        +1

Impacted Files	Coverage Δ	Complexity Δ
...tmutpileup/ValidateBasicSomaticShortMutations.java	80.172% <25%> (-0.529%)	19 <0> (ø)
...oadinstitute/hellbender/utils/gcs/BucketUtils.java	80.488% <0%> (-0.61%)	42% <0%> (ø)