X87: VectorICs: megamorphic keyed loads in crankshaft don't need a vector.

port 776770c0 (r27827).

original commit message:

  This needs "Pass load ic state through the Oracle"
  (https://codereview.chromium.org/1083933002/) to land first.

BUG=

Review URL: https://codereview.chromium.org/1093433004

Cr-Commit-Position: refs/heads/master@{#27873}