Reconstructing which stdlib object is used within an asm.js
module seems wasteful, given the typer has already checked this.
Preserving this information in a form that can be queried in
the asm-wasm-builder which generating code.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-asm-validator, test-parsing
R=titzer@chromium.org,marja@chromium.org,aseemgarg@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1508003002

Cr-Commit-Position: refs/heads/master@{#32687}