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: I97046aa51f1b3fc100e2eb2fa115f1bf8ae6437d
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>