Update remaining references to the NPAPI test plugin

BUG=331302
R=tfarina@chromium.org

Review URL: https://codereview.chromium.org/153583003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248770 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248770