DevTools: Fix breakpoints in source mapped files after reload.

Note: Test expectations change for the testBreakpointInCollectedReload test
are not caused by the change, but by the change in test harness.
These changes reveal an error in BreakpointManager implementation that will be fixed in the following patch.

BUG=388131
R=sergeyv

Review URL: https://codereview.chromium.org/350403004

git-svn-id: svn://svn.chromium.org/blink/trunk@177033 bbb929c8-8fbe-4397-9dbb-9b2b20218538