Skip the tst_QRegularExpression::threadSafety test on WASM temporarily

The test needs investigation. Skip it for now so that we can enable
CI for WASM but leave a note to investigate it.

Task-number: QTBUG-109954
Change-Id: I445996e969e7016a4d92a7e70da10b6d84a0fc71
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

tests/auto/corelib/text/qregularexpression/tst_qregularexpression.cpp

@@ -2389,6 +2389,10 @@ void tst_QRegularExpression::threadSafety_data()
 
 void tst_QRegularExpression::threadSafety()
 {
+#if defined(Q_OS_WASM)
+    QSKIP("This test misbehaves on WASM. Investigation needed (QTBUG-110067)");
+#endif
+
     QFETCH(QString, pattern);
     QFETCH(QString, subject);