DevTools: even more logging for jump-to-previous-editing-location.html test

Follow-up to r174282 to add some more logging into the test to figure out
why the test fails from time to time. The core problem seems to be due to
inconsistency in SimpleHistoryManager.
The patch be reverted after the reason will be determined.

BUG=361588
TBR=vsevik

Review URL: https://codereview.chromium.org/298723005

git-svn-id: svn://svn.chromium.org/blink/trunk@174502 bbb929c8-8fbe-4397-9dbb-9b2b20218538