Move error_prone config to external/error_prone

The error_prone config will likely need to be updated at the same
time as the error_prone prebuilts, so move the config into the same
project.  This requires jumping through some hoops because
external/error_prone may not be present in all manifests.

Bug: 64489631
Test: m -j RUN_ERROR_PRONE=true
Change-Id: I0d39da30e88bfbd849002956066021f380e48f7b
3 files changed
tree: 8b001ef07604fd442fc23631720cbec51a1b99d6
  1. checkerframework/
  2. error_prone/
  3. javac/
  4. jFormatString/
  5. soong/
  6. Android.bp