The DoubleToFloat32 helper takes care of everything, so use it
consistently.

Bug: chromium:969498
Change-Id: If71e5374684b89615006548cb0329f4d4cb7fd6d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1648253
Commit-Queue: Ben Smith <binji@chromium.org>
Reviewed-by: Ben Smith <binji@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62062}