Before testserver becomes a stable feature, let's keep testserver.prf in
"mkspecs/features/unsupported". The test server's shared files will be
stored in "mkspecs/features/data/testserver".
Because the path of testserver has been changed, all the tests relying
on the docker servers should be updated as well.
Change-Id: Id2494d2b58ee2a9522d99ae61c6236021506b876
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
