QThread: add empty functions for the no-thread build

Add implementation for requestInterruption() and
isInterruptionRequested().

Pick-to: 6.4
Change-Id: I9ffabb0181a48c71deded7362c6c8e2e96418cc0
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/thread/qthread.cpp

@@ -979,6 +979,16 @@ bool QThread::isRunning() const
     return d->running;
 }
 
+void QThread::requestInterruption()
+{
+
+}
+
+bool QThread::isInterruptionRequested() const
+{
+    return false;
+}
+
 // No threads: so we can just use static variables
 Q_CONSTINIT static QThreadData *data = nullptr;