Trampoline ICs differ from normal ICs only in that they
load the feedback vector from the stack instead of accepting it
as an argument. We created them for FullCodeGen, where you always
have the feedback vector on the stack, and can reduce the amount
of code required to invoke an ICs by hiding the stack load down
in the trampoline IC.

Now the concept isn't really necessary, and we can achieve a
nice cleanup of our idea-space by removing it. The first step is
to remove their usage in TurboFan.

Bug: v8:7199
Change-Id: I08aefa5de199b1f19adea261b7086a84338c0805
Reviewed-on: https://chromium-review.googlesource.com/822193Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50038}