Initial support for PolyNull

[msridhar]

Fixes #1616

[msridhar]

This change is part of the following stack:

• Initial support for PolyNull #1813 ◀

_{Change managed by git-spice.}

[codecov]

Codecov Report

❌ Patch coverage is 91.90601% with 31 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.80%. Comparing base (f866bc9) to head (a63ed66).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...ava/com/uber/nullaway/generics/GenericsChecks.java	90.96%	6 Missing and 8 partials ⚠️
.../com/uber/nullaway/generics/PolyNullInference.java	90.42%	3 Missing and 6 partials ⚠️
...m/uber/nullaway/handlers/LibraryModelsHandler.java	92.30%	1 Missing and 2 partials ⚠️
...r/nullaway/librarymodel/NestedTypePathUpdater.java	85.00%	1 Missing and 2 partials ⚠️
...src/main/java/com/uber/nullaway/LibraryModels.java	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #1813      +/-   ##
============================================
+ Coverage     87.69%   87.80%   +0.10%     
- Complexity     3450     3522      +72     
============================================
  Files           110      111       +1     
  Lines         11475    11797     +322     
  Branches       2355     2406      +51     
============================================
+ Hits          10063    10358     +295     
- Misses          652      664      +12     
- Partials        760      775      +15     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.