Original commit message:
[turbofan] Improve representation selection for type guard.
This takes into account the type of the type guard when choosing
representation for a node. To make the representation changes
unambiguous, we pass the restricted type to the changer.
BUG=chromium:726554
Review-Url: https://codereview.chromium.org/2920193004
Cr-Commit-Position: refs/heads/master@{#45734}
PR-URL: https://github.com/nodejs/node/pull/15177
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>