This check whether a function is being debugged is obsolete. For the
optimization path it is covered by a bailout further down. The lookup
within the optimized code map doesn't need to be covered, because that
map is guaranteed to stay empty while break slots are present.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1907923003

Cr-Commit-Position: refs/heads/master@{#35694}