X87: CheckPrototypes uses weak cells to embed maps.
X87: CheckPrototypes uses weak cells to embed maps.

port 062a032f50291ce181462226ff41b4ef9b11deba

original commit message:

  CheckPrototypes uses weak cells to embed maps.

BUG=

Review URL: https://codereview.chromium.org/761093004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#25648}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh