With --wasm-trace-memory, both compiled code and the interpreter will
output each memory load or store. This helps to debug miscompilations in
emscripten or in V8, like the referenced bug.

R=titzer@chromium.org

Bug: chromium:718858
Change-Id: I90704d164975b11c65677f86947ab102242d5153
Reviewed-on: https://chromium-review.googlesource.com/684316Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48255}