Both the JSTypeFeedbackSpecializer and the JSTypeFeedbackLowering is
dead code by now, since the more general JSNativeContextSpecialization
deals with the property/global load/store type feedback in a way that
also interacts properly with inlining.

BUG=v8:4470
LOG=n
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1407913003 .

Cr-Commit-Position: refs/heads/master@{#31462}