Remove removed auto_testfile.h from breakpad.gyp.

With chromium r238524 breakpad was rolled to r1240. In breakpad r1240 the
file auto_testfile.h was removed. This CL removes this file from the gyp
file for breakpad in chromium.

R=blundell@chromium.org, mark@chromium.org

Review URL: https://codereview.chromium.org/104913003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238710 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238710