Make new ARMv7 strcmp code NaCl-friendly

Recent upstream changes to the ARMv7 strcmp made it break when
compiled for non-Thumb ARM.  This brings in the same fixes I made
to the glibc version of the identical code when the same changes
from the ARM folks went in there.

BUG= none
TEST= disassembly identical to tested glibc version
R=binji@chromium.org

Review URL: https://codereview.chromium.org/303423005
1 file changed