Revert of Update remaining references to the NPAPI test plugin (https://codereview.chromium.org/153583003/)

Reason for revert:
Caused a build break:
http://build.chromium.org/p/chromium.chrome/builders/Google%20Chrome%20Mac/builds/16265

File /Volumes/data/b/build/slave/google-chrome-rel-mac/build/src/out/Release/plugins/TestNetscapePlugIn.plugin doesn't exist

Original issue's description:
> Update remaining references to the NPAPI test plugin
> 
> BUG=331302
> R=tfarina@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248770

TBR=tfarina@chromium.org,jochen@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=331302

Review URL: https://codereview.chromium.org/155153002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248808 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248808