Buildbot: Explicitly disable tests on all platforms

They were never running anyway since there's no checkout of
tests folder. We should either make tweaks to buildbot master
to make it to send cloning commands for tests folder and keep
tests working (currently some of them are broken).

build_files/buildbot/slave_test.py

@@ -35,9 +35,8 @@ blender_dir = '../blender.git'
 if "cmake" in builder:
     # cmake
 
-    if "linux" in builder or 'mac' in builder:
-        print("Automated tests are still DISABLED!")
-        sys.exit(0)
+    print("Automated tests are still DISABLED!")
+    sys.exit(0)
 
     build_dir = os.path.abspath(os.path.join('..', 'build', builder))
     chroot_name = None