This is a rewrite of the ASM validator. This one follows the spec instead of using the AST visitors.

BUG= https://bugs.chromium.org/p/v8/issues/detail?id=4203
TEST=cctest/asmjs/test-asm-typer
TEST=cctest/asmjs/test-typing-asm
LOG=N

Review-Url: https://codereview.chromium.org/2071343003
Cr-Commit-Position: refs/heads/master@{#37694}