Migrate network access tests to new test server

That includes the tests in

• kernel/qhostinfo/tst_qhostinfo.cpp
• access/qabstractnetworkcache/tst_qabstractnetworkcache.cpp
• access/qhttpnetworkconnection/tst_qhttpnetworkconnection.cpp
• access/qnetworkreply/tst_qnetworkreply.cpp
• access/spdy/tst_spdy.cpp

but possibly additional tests.