events: Cleanup: Rename events_unittests.cc to run_all_unittests.cc

run_all_unittests.cc is name more common for that kind of main entry.

BUG=None
TEST=events_unittests
R=sadrul@chromium.org

Review URL: https://codereview.chromium.org/103303008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239798 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239798