Indicate that QTestLib is running

Set QT_QTESTLIB_RUNNING=1 on QTestLib startup.

This allows Qt to adapt its behavior to the testing
environment, WHICH IS NORMALLY NOT SOMETHING YOU WANT
TO DO. Use with caution.

Change-Id: I31de80e7c2cc91ff1ed8137926e6b729ef6efdc6
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

src/testlib/qtestcase.cpp

@@ -2367,6 +2367,7 @@ static LONG WINAPI windowsFaultHandler(struct _EXCEPTION_POINTERS *exInfo)
 static void initEnvironment()
 {
     qputenv("QT_LOGGING_TO_CONSOLE", "1");
+    qputenv("QT_QTESTLIB_RUNNING", "1");
 }
 
 /*!