The libcorkscrew stack unwinder does not understand cfi directives,
so add .save directives so that it can function properly.
Also add the directives in to strcmp.S and fix a missing set of
directives in cortex-a9/memcpy_base.S.
Bug: 10345269
Merge from internal master.
(cherry-picked from 5f7ccea3ffab05aeceecb85c821003cf580630d3)
Change-Id: If48a216203216a643807f5d61906015984987189