TurboFan can indeed comsume NumberOrOddball feedback for abstract
relational comparisons, so we should just provide it from Ignition.

Drive-by-fix: Add a DCHECK to protect against abstract/strict equality
number comparison accidentially utilizing Oddball feedback.

BUG=v8:5267,v8:5400
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2518283002
Cr-Commit-Position: refs/heads/master@{#41166}