Currently, V8 uses the same counter to count both wasm and and asm js. This
splits the counters into two separate counters, and then uses the appropriate
counter when instantiating the module.

BUG=chromium:704922
R=bbudge@chromium.org,bradnelson@chromium.org

Review-Url: https://codereview.chromium.org/2777073003
Cr-Commit-Position: refs/heads/master@{#44164}