Avoid printing three stack traces on CHECK failure. Print just one.

BUG=332468
R=brettw@chromium.org

Review URL: https://codereview.chromium.org/134133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244564 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244564
Clean up TestLauncherDelegate.

BUG=236893
R=sky@chromium.org

Review URL: https://codereview.chromium.org/133653002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244566 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244566