PPC: Remove unnecessary options from HTailCallThroughMegamorphicCache

Port e0844a24

Original commit message:
These options were added for a hydrogen code stub version of
the VectorIC dispatcher, which was discontinued.

R=mvstanton@chromium.org, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1088573002

Cr-Commit-Position: refs/heads/master@{#27797}