Port 56d90782

Original commit message:

    In Crankshaft, we would install special ICs that didn't need a vector and slot
    in the MEGAMORPHIC case. This optimization limits our hand against future
    improvements.

R=mvstanton@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Review-Url: https://codereview.chromium.org/2023983002
Cr-Commit-Position: refs/heads/master@{#36600}