StrictUnusedVariable should respect -XoptIgnoreSuppressionAnnotations; @SuppressWarnings("UnusedVariable") no longer suppresses StrictUnusedVariable

[kelvinou01]

Before this PR

1. StrictUnusedVariable opts out of SuppressibleTreePathScanner's suppression mechanism, and checks for suppressions manually. This interferes with suppressible-error-prone's removeUnused mode, which relies on modifying SuppressibleTreePathScanner.
2. StrictUnusedVariable has a quirky setup to deal with alt-names, so that@SuppressWarnings("UnusedVariable") suppresses it, but errorProneOpotions.disable("UnusedVariable") does not disable it. This also interferes with RemoveUnused mode, as it doesn't know @SuppressWarnings("UnusedVariable") is a suppression for StrictUnusedVariable

After this PR

1. I think UnusedVariable (from which StrictUnusedVariable is mostly copied from) didn't use SuppressibleTreePathScanner because the class was new at the time (2022), but now we can switch to using SuppressibleTreePathScanner to get our modifications
2. It is reasonable that @SuppressWarnings("UnusedVariable") should only suppress UnusedVariable, @SuppressWarnings("StrictUnusedVariable") should only suppress StrictUnusedVariable, and SuppressWarnings("unused") is the catch-all suppression for all unused checks (including UnusedMethod). Let's implement this behavior so removeUnused mode can work with StrictUnusedVariable.

==COMMIT_MSG==
StrictUnusedVariable should respect -XoptIgnoreSuppressionAnnotations; @SuppressWarnings("UnusedVariable") no longer suppresses StrictUnusedVariable
==COMMIT_MSG==

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Description

StrictUnusedVariable should respect -XoptIgnoreSuppressionAnnotations

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🐛 Fixes

• StrictUnusedVariable should respect -XoptIgnoreSuppressionAnnotations (#3384)

[kelvinou01]

When this rolls out, places with @SuppressWarnings("UnusedVariable") will additionally suppress for-rollout:StrictUnusedVariable. Then, when removeUnused mode is fixed, we can remove the unused suppressions on UnusedVariable.

[kelvinou01]

DO NOT MERGE (YET)

We're currently moving all the error-prone infrastructure in gradle-baseline (including baseline-error-prone, baseline-nullaway) to https://github.com/palantir/baseline-error-prone. This PR should be opened in the new repository once setup is completed.

[kelvinou01]

Hey there, our error-prone infrastructure has been moved to https://github.com/palantir/baseline-error-prone.