Fix ReturnValueIgnored errorprone issues

https://errorprone.info/bugpattern/ReturnValueIgnored

Bug: 253827323
Flag: EXEMPT bugfix
Test: RUN_ERROR_PRONE=true m javac-check
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d96c7f200686298b4502e4276e8659352aef589e)
Merged-In: I8147c72bc9bd578c4c564e9d6e3dd4b2e3999416
Change-Id: I8147c72bc9bd578c4c564e9d6e3dd4b2e3999416