WIP: Merge some of CRAMFileBAIIndexTest/CRAMFileCRAIIndexTest into a new CRAMFileIndexTest

[jmthibault79]

Description

CRAMFileBAIIndexTest and CRAMFileCRAIIndexTest have a lot of similarities. Let's refactor them and reduce the common code.

TODO: investigate some problems I found while doing this, marked by TODO in the tests.

TODO: This is an incomplete checkpoint PR. More work can be done in this area.

Checklist

• [ ] Code compiles correctly
• [ ] New tests covering changes and new functionality
• [ ] All tests passing
• [ ] Extended the README / documentation, if necessary
• [ ] Is not backward compatible (breaks binary or source compatibility)

[codecov-io]

Codecov Report

Merging #1338 into master will increase coverage by 0.021%. The diff coverage is n/a.

@@               Coverage Diff               @@
##              master     #1338       +/-   ##
===============================================
+ Coverage     67.822%   67.843%   +0.021%     
- Complexity      8258      8260        +2     
===============================================
  Files            562       562               
  Lines          33663     33663               
  Branches        5644      5644               
===============================================
+ Hits           22831     22838        +7     
+ Misses          8658      8652        -6     
+ Partials        2174      2173        -1

Impacted Files	Coverage Δ	Complexity Δ
...samtools/util/AsyncBlockCompressedInputStream.java	76% <0%> (+4%)	13% <0%> (+1%)	:arrow_up:
...jdk/samtools/cram/structure/ContainerHeaderIO.java	83.333% <0%> (+8.333%)	6% <0%> (+1%)	:arrow_up:

[cmnbroad]

Obsoleted by https://github.com/samtools/htsjdk/pull/1440.