Try to remove SuppressWarnings("GuardedBy")

#6566 introduced suppressions to allow being compatible with newer versions of Error Prone. But we should spend some time to see if we could tweak the code so that the suppressions would be unnecessary.

If we can't remove them or if it would make the code worse, we can leave them as-is and close this issue.

Start by reviewing issue #6566 and the suppressions it introduced for newer Error Prone compatibility. Trace each SuppressWarnings("GuardedBy") use and assess whether the surrounding code can be adjusted without making it worse. Done means removing the suppressions where safe, or documenting that they should remain and closing the issue.

Scritto dal modello di indicizzazione a partire dal testo della issue.