Java unit test : Fix & enforce some errorprone

* JavaUtilDate -> Mostly a silent because I do not want to rewrite all
  tests for now, just prevent expending a wrong usage
* DirectInvocationOnMock

Bug: 344658662
Test: m framework-bluetooth
Flag: Exempt following errorprone recommendation
Change-Id: I338d7a5faf1335919e2d75f5637b8bef7dcd77b3