During codegen, we build a list mapping protected instructions to their
associated landing pads. This will ultimately by used by the signal handler to
recover from out of bounds faults and throw a JS exception.

This is mostly pulled from my larger in-progress CL at
https://codereview.chromium.org/2371833007/.

BUG= https://bugs.chromium.org/p/v8/issues/detail?id=5277

Review-Url: https://codereview.chromium.org/2500443004
Cr-Commit-Position: refs/heads/master@{#41400}