This prepares a patch to throw actual errors instead of just strings on
wasm traps. In order to accomplish this, the messages need to be known
to the runtime, as the generated code will just pass the message id.

R=mstarzinger@chromium.org, titzer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1880493002

Cr-Commit-Position: refs/heads/master@{#35628}