Handle:
* mem{cpy,move,set} (without optimizations for known lengths)
* nacl.read.tp
* setjmp, longjmp
* trap

Mostly see if the dispatching/organization is okay.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3882
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/321993002