The wasm valiation incorrectly allowed simd locals, even without the
experimental flag turned on. This was not noted in the generated code
because simd opcodes were forbidden, but the interpreter could not
handle these locals.

R=clemensh@chromium.org

Bug: chromium:763697
Change-Id: I11d924ac21e50bce81d0504c2c7b252105a89f80
Reviewed-on: https://chromium-review.googlesource.com/660117
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47946}