libc_api: guest stubs for mem* routines

To facilitate proxying for them.

Test: spec2000, geekbench
Bug: 248619205
Bug: 200327919
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:76c826196172fbdca8c8bd6328a33793c2900998)
Merged-In: Ibea3f83273a9fa75a5c3354c697bd0b1d11bd5f3
Change-Id: Ibea3f83273a9fa75a5c3354c697bd0b1d11bd5f3
2 files changed