[wasm][asm.js] Fix bad asm.js in layout tests.

This causes validation failures breaking the test expectations
when the new asm.js -> wasm pipeline is turned on.

BUG=v8:4203
R=danno@chromium.org,machenbach@chromium.org,binji@chromium.org

Review-Url: https://codereview.chromium.org/2624863003
Cr-Commit-Position: refs/heads/master@{#443047}
1 file changed