DevTools: more excessive dumping for jump-to-previous-position.html test

This patch, as well as r174171, adds even more excessive dumping for
jump-to-previous-position.html test.
The changes are expected to be reverted as the reason of failures will
be detected.

BUG=361588

Review URL: https://codereview.chromium.org/290393002

git-svn-id: svn://svn.chromium.org/blink/trunk@174282 bbb929c8-8fbe-4397-9dbb-9b2b20218538