M2 STR filter also looks at insertions

[davidbenjamin]

@takutosato Here's another little one. This didn't affect sensitivity in Hapmap or DREAM and in DREAM it reduced indel false positives by about half. Not a bad short-term improvement for MC3, although deep learning will handle it better.

[codecov-io]

Codecov Report

Merging #4845 into master will decrease coverage by 0.005%.
The diff coverage is 100%.

@@               Coverage Diff               @@
##              master     #4845       +/-   ##
===============================================
- Coverage     80.374%   80.369%   -0.005%     
+ Complexity     17677     17675        -2     
===============================================
  Files           1088      1088               
  Lines          64006     64006               
  Branches       10312     10312               
===============================================
- Hits           51444     51441        -3     
- Misses          8554      8557        +3     
  Partials        4008      4008

Impacted Files	Coverage Δ	Complexity Δ
...r/tools/walkers/mutect/Mutect2FilteringEngine.java	82.237% <100%> (ø)	41 <0> (ø)	⬇️
...utils/smithwaterman/SmithWatermanIntelAligner.java	50% <0%> (-30%)	1% <0%> (-2%)