We cannot remove a speculative operation when it's type relies on it to deopt.
Fix this by only relying on the lowering to remove operations.

Bug: chromium:786521
Change-Id: I2cf45e8d45b76cfeb06e6329f323cade74719124
Reviewed-on: https://chromium-review.googlesource.com/793043Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49882}