IPC fuzzer: ignore files other than ipcdumps in a CF data bundle.

BUG=260848

Review URL: https://codereview.chromium.org/139493005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247395 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247395