This patch provides a new implementation of popcnt and ctz in the case
where the platform does not provide these instructions. Instead of
building a TF graph which implements it we now call a C function.

Additionally I turned on additional tests in test-run-wasm-64.cc

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1857363003

Cr-Commit-Position: refs/heads/master@{#35685}