Tailor Java extractor for Android builds.

Most of the changes reduce dependencies on open source Java libraries
developed at Google but absent from AOSP: flogger, re2j and protobuf v3.
In addition, there are few minor bug fixes to be added to the upstream
code: 1) Handle javac's -Akey=val option; 2) Make .kt valid source file
reference; 3) Always pass -XDStringConcat=inline option to javac

Bug: 121267023
Test: Run prebuilts/build-tools/build-prebuilts.sh, copy javac_extractor.jar
to the AOSP tree and run 'm xref_java' there

Change-Id: I46ca627323e8bf01311aa0b6e0ef44250777faa6
9 files changed