Revert "Turn uses of `COVERAGE_PATHS` and `COVERAGE_EXCLUDE_PATHS` into errors."

This reverts commit ace58607.

Reason for revert: Droidcop-triggered revert due to breakage https://android-build.googleplex.com/builds/quarterdeck?branch=git_rvc-dev-plus-aosp&target=build_test3&lkgb=6662220&lkbb=6662382&fkbb=6662228
Bug: 158212027
Bug: 160769227
Test: N/A revert
Change-Id: I0d366adcc735e9cc417d28013afb0386dea1fa64