Add a method to conditionally apply a Consumer on a nullable input

[yfarjoun]

Description

Please explain the changes you made here. Explain the motivation for making this change. What existing problem does the pull request solve?

Things to think about before submitting:

• [ ] Make sure your changes compile and new tests pass locally.
• [ ] Add new tests or update existing ones:
  • A bug fix should include a test that previously would have failed and passes now.
  • New features should come with new tests that exercise and validate the new functionality.
• [ ] Extended the README / documentation, if necessary
• [ ] Check your code style.
• [ ] Write a clear commit title and message
  • The commit message should describe what changed and is targeted at htsjdk developers
  • Breaking changes should be mentioned in the commit message.

[codecov-io]

Codecov Report

Merging #1419 into master will increase coverage by 0.318%. The diff coverage is 83.333%.

@@               Coverage Diff               @@
##              master     #1419       +/-   ##
===============================================
+ Coverage     68.127%   68.445%   +0.318%     
- Complexity      8381      8673      +292     
===============================================
  Files            573       573               
  Lines          33985     34873      +888     
  Branches        5668      5930      +262     
===============================================
+ Hits           23153     23869      +716     
- Misses          8643      8783      +140     
- Partials        2189      2221       +32

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/htsjdk/samtools/util/IOUtil.java	61.689% <ø> (+3.276%)	196 <0> (+76)	:arrow_up:
src/main/java/htsjdk/samtools/util/CodeUtil.java	71.429% <83.333%> (+4.762%)	4 <4> (+2)	:arrow_up:
...htsjdk/samtools/util/nio/DeleteOnExitPathHook.java	86.667% <0%> (-3.81%)	5% <0%> (+1%)
.../htsjdk/samtools/util/AbstractRecordAndOffset.java	81.081% <0%> (-2.919%)	15% <0%> (+6%)
...in/java/htsjdk/samtools/util/SamLocusIterator.java	90.588% <0%> (-1.193%)	23% <0%> (ø)
.../variant/variantcontext/VariantContextBuilder.java	81.992% <0%> (-0.949%)	75% <0%> (+35%)
.../htsjdk/variant/variantcontext/VariantContext.java	79.668% <0%> (+1.664%)	345% <0%> (+108%)	:arrow_up:
...c/main/java/htsjdk/samtools/liftover/LiftOver.java	85.167% <0%> (+2.31%)	44% <0%> (+13%)	:arrow_up:
.../samtools/reference/AbstractFastaSequenceFile.java	60% <0%> (+2.5%)	18% <0%> (+6%)	:arrow_up:
src/main/java/htsjdk/variant/vcf/VCFEncoder.java	88.652% <0%> (+2.794%)	96% <0%> (+28%)	:arrow_up:
... and 3 more