tests: eliminated usage of qttest_p4.prf

tests: eliminated usage of qttest_p4.prf

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: I7e6c67674ec669ad1ba7286648c7b4a501f4201c
Reviewed-on: http://codereview.qt-project.org/6185
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>