This CL adds the --trace-wasm-lazy-compilation flag, to track which
function is being compiled, and how many locations in the caller and in
function tables are actually being patched.
It seems that we currently don't patch the caller correctly when
calling through wasm-to-wasm stubs, and this tracing helps to find the
issue.

Drive-by: Fix order and location of macro undefs.

R=titzer@chromium.org

Bug: chromium:788441
Change-Id: I6091c0d490a729f8e3cb759cd661cf52129d2211
Reviewed-on: https://chromium-review.googlesource.com/793157Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49669}