This changes the parser to keep around bodies for asm.js functions when
then asm.js validator is turned on. Eventually the validator will work
on one function at a time, but for now we validate the entire module at
once.

R=rossberg@chromium.org

Review-Url: https://codereview.chromium.org/1981333003
Cr-Commit-Position: refs/heads/master@{#36291}