Remove qttest_p4.prf file

Remove qttest_p4.prf file

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.

Most autotest .pro files should look like this:

  CONFIG += testcase
  TARGET = tst_something
  QT = core testlib
  SOURCES = tst_something.cpp

Change-Id: I051b230c5c4fd56dc6eae2b9b7bdff6c033248fd
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>