Android is all-PIC/PIE.

Clean up the x86/x86_64 assembler. The motivator (other than reducing
confusion) was that asm.h incorrectly checked PIC rather than __PIC__.

Bug: 16823325

(cherry picked from commit 6b6364a7fc7c3ba37ee907776a29bdc8c9793db9)

Change-Id: I89ca57fa0eb34a36de6cb11ea85f71054fce709d
7 files changed