This is a first step to make basic block profiling work in wasm. More
is needed, including eventually making the profiler thread safe.

Change-Id: Ic216c881a4ab5a633e147e5538bb405c32e687cd
Reviewed-on: https://chromium-review.googlesource.com/1150234
Commit-Queue: Stephan Herhut <herhut@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54728}