ProtoLog improvements

- Added log statement location info to viewer config
- Fixed a NPE in ProtoLogImpl
- Reworked early return for log calls
- Changed type of message hash field to signed (for Java compat)
- Fix flaky tests for ProtoLogImpl

Bug:
Test: atest protologtool-tests FrameworksServicesTests:com.android.server.protolog
Change-Id: I7874475083ab5d01fe46fd3013a058743acd3884