master
Address remaining https://errorprone.info/bugpattern/AssignmentExpression warnings.
Avoid testing identity equality on `Boolean` instances.
Remove view caching from `CompactHashMap`.
Remove more [`throws` clauses for exceptions that aren't thrown](https://errorprone.info/bugpattern/CheckedExceptionNotThrown).
Rename the remaining `PackageSanityTests` (plural) classes to "`PackageSanityTest`" (singular).
More aggressively throw `NullPointerException` in `common.graph`.
Address some more counterfactual [CheckedExceptionNotThrown](https://errorprone.info/bugpattern/CheckedExceptionNotThrown) findings.
Adapt to the once and future TODO style.
Add HttpHeaders constants for on-prefetch-activation.
Tidy up `ExecutionSequencerTest`: