Moving back to Stock toolchain

Revert "Fix a variety of small publicly-reported bugs."

This reverts commit f3556922649d88f66c1f00fe206dc395419c1e31.

Revert "build core/jni with fstrict-aliasing"

This reverts commit 892bf4dbeeb0150cceb644dbf97a71f448c159c5.

Revert "Fix one and hide the other warnings from core/jni"

This reverts commit 79b9d3cfedbe6236cc4127a85f79d6ea8d7f8966.

Revert "Fixes for clang:"

This reverts commit bfd9fe2db4bb32184a334b773d2985af411e140b.

Revert "frameworks/base: Fix aliasing violations"

This reverts commit 3f93054fd4f8877e848d4a2100b34c805ed2047f.

Revert "Vectorize bitmap operations on A15 too"

This reverts commit b20ec2ee2099b8253838acac57c6450ae577b19a.

Revert "frameworks/base: vectorize Bitmap operations"

This reverts commit 5b7cddf9b8bef2477ecb8ad1d4969ff1613a2f76.

Revert "GC triggering performance optimizations"

This reverts commit 2868eec6a0fa249729f95c333339ca3a1e6c15d3.