wasm: fix single thread build

Fixes linking of apps

Change-Id: I9bbec9b63af8ae2801643fe124aeda8b25abeca5
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
(cherry picked from commit ae3506d80e11068957af38897e451cddb18bbe70)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 6c4fe5766e26bdedf8085816eeeecaa8f75c3d9c)

src/corelib/thread/qthread.cpp

@@ -999,6 +999,10 @@ bool QThread::isInterruptionRequested() const
     return false;
 }
 
+void QThread::setTerminationEnabled(bool)
+{
+}
+
 // No threads: so we can just use static variables
 Q_CONSTINIT static QThreadData *data = nullptr;