Require that foreign variable imports have a correct type annotation,
_including_ checking the value of the multiplier is 0 or 1.0 as appropriate.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-asm-validator
R=aseemgarg@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1691723004

Cr-Commit-Position: refs/heads/master@{#33923}