Removed redundant readability test in unrollPaths method

[yfarjoun]

Cloud paths are slow to provide readability. This PR removes a readability check that comes right before opening a file. A failure to read the file will result in an error in both cases.

[codecov-io]

Codecov Report

Merging #1355 into master will increase coverage by 0.716%. The diff coverage is 25%.

@@               Coverage Diff               @@
##              master     #1355       +/-   ##
===============================================
+ Coverage     67.848%   68.564%   +0.716%     
- Complexity      8283      8805      +522     
===============================================
  Files            563       564        +1     
  Lines          33706     35024     +1318     
  Branches        5657      6012      +355     
===============================================
+ Hits           22869     24014     +1145     
- Misses          8659      8783      +124     
- Partials        2178      2227       +49

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/htsjdk/samtools/util/IOUtil.java	58.111% <25%> (-0.101%)	118 <0> (ø)
...s/cram/encoding/external/ExternalLongEncoding.java	61.538% <0%> (-5.128%)	4% <0%> (+1%)
src/main/java/htsjdk/variant/bcf2/BCFVersion.java	93.103% <0%> (-1.633%)	12% <0%> (+5%)
src/main/java/htsjdk/samtools/SAMFileHeader.java	66.942% <0%> (-0.5%)	83% <0%> (+38%)
...dk/samtools/cram/structure/SubstitutionMatrix.java	91.026% <0%> (-0.279%)	30% <0%> (+15%)
...s/cram/encoding/external/ExternalByteEncoding.java	100% <0%> (ø)	10% <0%> (+4%)	:arrow_up:
...ram/encoding/external/ExternalIntegerEncoding.java	100% <0%> (ø)	10% <0%> (+4%)	:arrow_up:
...tools/cram/encoding/external/ExternalEncoding.java	100% <0%> (ø)	2% <0%> (?)
...c/main/java/htsjdk/samtools/util/IntervalList.java	73.913% <0%> (+0.016%)	103% <0%> (+34%)	:arrow_up:
...n/java/htsjdk/samtools/cram/structure/SliceIO.java	84.524% <0%> (+1.19%)	15% <0%> (+1%)	:arrow_up:
... and 17 more