Revert of Use weak cells in map checks in polymorphic ICs. (patchset #8 id:140001 of https://codereview.chromium.org/753993003/)

Reason for revert:
[Sheriff] Speculative revert for breaking chromium asan (roll blocker):
http://build.chromium.org/p/client.v8/builders/Linux%20ASan%20LSan%20Tests%20%281%29/builds/1683

Original issue's description:
> Use weak cells in map checks in polymorphic ICs.
>
> BUG=v8:3663
> LOG=N

TBR=mvstanton@chromium.org,akos.palfi@imgtec.com,weiliang.lin@intel.com,ulan@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=v8:3663

Review URL: https://codereview.chromium.org/771033003

Cr-Commit-Position: refs/heads/master@{#25597}