Because the parser optimizes !123 -> false,
we allow booleans in expressions (but not parameter annotations).
Allow this in asm-wasm-builder.
Turn on an early out case in asm-typer that is fine.

BUG=672784
R=titzer@chromium.org

Review-Url: https://codereview.chromium.org/2561193003
Cr-Commit-Position: refs/heads/master@{#41622}