This avoids the EffectControlLinearizer stumbling upon unreachable
code.

Bug: chromium:958718
Change-Id: I135c17813741e48e878a4624370eee1e06081031
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1605737Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61434}