The Oddball::to_number_raw field contains the actual double value of the
Oddball converted to a number, and is located at the same offset as the
HeapNumber::value field, so for lowering changes we don't need to check
for undefined (or any other oddball explicitly).

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1922443002

Cr-Commit-Position: refs/heads/master@{#35753}