[GTK] [EFL] Install TestNetscapePlugin apart from the other libs.
https://bugs.webkit.org/show_bug.cgi?id=137212

This moves TestNetscapePlugin to a new folder (lib/plugins).
We should not use the same directory for TestNetscapePlugin and
the other libraries, because we end up scanning all the .so in the
lib dir for every test.

Reviewed by Carlos Garcia Campos.

* DumpRenderTree/TestNetscapePlugIn/CMakeLists.txt: Set LIBRARY_OUTPUT_DIRECTORY to lib/plugins.
* Scripts/webkitpy/port/efl.py:
(EflPort.setup_environ_for_server): Update plugin path.
* Scripts/webkitpy/port/gtk.py:
(GtkPort.setup_environ_for_server): Update plugin path.
* TestWebKitAPI/Tests/WebKit2Gtk/CMakeLists.txt: Update plugin path.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@174093 268f45cc-cd09-0410-ab3c-d52691b4dbfc