They violate the style guide, and cause problems for jumbo builds.
This CL removes all occurrences in src/wasm except for the file
wasm-objects.cc, which is a bit more involved and will be fixed in a
separate CL.

R=titzer@chromium.org
CC=mostynb@opera.com

Bug: chromium:746958
Change-Id: If5d9c03e0d6fa364e1d21feda49773468a48fba6
Reviewed-on: https://chromium-review.googlesource.com/645707
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47743}