Instead of modifying this flag in compiled wasm code, we can just
change it in the caller / called code. This saves code space and
compilation time and fixes the referenced bug.

R=titzer@chromium.org, eholk@chromium.org

Bug: chromium:773631, v8:5277
Change-Id: I095158ac01eecd21a92649a3990e8d7c593db912
Reviewed-on: https://chromium-review.googlesource.com/712597Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Eric Holk <eholk@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48602}