For asm.js we now have a dedicated AsmTyper, that uses it's own type
system (which is tailored towards asm.js), and so we don't need the
special asm.js types anymore in the TypeCache. This also moves the
TypeCache into the src/compiler directory, because it doesn't make
sense to use outside anyways.

TBR=ahaas@chromium.org
R=jarin@chromium.org
BUG=v8:5267

Review-Url: https://codereview.chromium.org/2289573002
Cr-Commit-Position: refs/heads/master@{#38964}