Bug: http://b/77320844
Android.mk doesn't have support for PGO either. This causes linker
error (about missing __llvm_profile symbols) in the PGO-instrumentation
enabled builds in the release branch.
Test: m ANDROID_PGO_INSTRUMENT=ALL
Change-Id: I84fda4f1ac4f00ac26869507c6f5640b4ec9f6f3