qttest_p4.prf was added as a convenience for Qt's own autotests in Qt4.
It enables various crufty undocumented magic, of dubious value.
Stop using it, and explicitly enable the things from it which we want.
Change-Id: I48ab0ee64d8348cada2e6c7b27c67b6bbc36280d
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>