Revert "Use CPP defines for default x86 and x86_64 ISA features"

This reverts commit 5b0bbf33180bbf9e7fbe8c952eda16096c637f8c.

Reason for revert: Broke target tests.

Bug: 155324337
Change-Id: I5e838294ce8ce72098e91d33ecb2cc090d28e6d7
3 files changed