The background parser checks for debugger state in its constructor. This
is not good enough, since the debugger state may change afterwards, but
before compiling takes place. As the background parser can only parse
lazily, this could mean that due to debugging, we try to eagerly compile
an inner function we have not eagerly parsed.

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/1247743002

Cr-Commit-Position: refs/heads/master@{#29784}