[GTK] [CMake] Build the WebKit1 GObject API tests

[GTK] [CMake] Build the WebKit1 GObject API tests
https://bugs.webkit.org/show_bug.cgi?id=125684

Reviewed by Daniel Bates.

.:

* Source/PlatformGTK.cmake: Added.

Source/WebKit/gtk:

* tests/CMakeLists.txt: Added.
* tests/testapplicationcache.c: Use the WTF config.h instead of including the autotools configuration directly.
* tests/testatk.c: Ditto.
* tests/testatkroles.c: Ditto.
* tests/testcontextmenu.c: Ditto.
* tests/testcopyandpaste.c: Ditto.
* tests/testdomdocument.c: Ditto.
* tests/testdomdomwindow.c: Ditto.
* tests/testdomnode.c: Ditto.
* tests/testdownload.c: Ditto.
* tests/testfavicondatabase.c: Ditto.
* tests/testglobals.c: Ditto.
* tests/testhittestresult.c: Ditto.
* tests/testhttpbackend.c: Ditto.
* tests/testkeyevents.c: Ditto.
* tests/testloading.c: Ditto.
* tests/testmimehandling.c: Ditto.
* tests/testnetworkrequest.c: Ditto.
* tests/testnetworkresponse.c: Ditto.
* tests/testwebbackforwardlist.c: Ditto.
* tests/testwebdatasource.c: Ditto.
* tests/testwebframe.c: Ditto.
* tests/testwebhistoryitem.c: Ditto.
* tests/testwebinspector.c: Ditto.
* tests/testwebplugindatabase.c: Ditto.
* tests/testwebresource.c: Ditto.
* tests/testwebsettings.c: Ditto.
* tests/testwebview.c: Ditto.
* tests/testwindow.c: Ditto.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@161015 268f45cc-cd09-0410-ab3c-d52691b4dbfc