tst_QSharedMemory::readOnly: Skip on macOS

The binary hangs rather than segfaults on that platform.

Task-number: QTBUG-59936
Change-Id: Id7d38edb7c746e3c0cd4b4941e0e19b3d42a628a
Reviewed-by: Jake Petroules <jake.petroules@qt.io>

tests/auto/corelib/kernel/qsharedmemory/test/tst_qsharedmemory.cpp

@@ -459,6 +459,8 @@ void tst_QSharedMemory::readOnly()
 {
 #if !QT_CONFIG(process)
     QSKIP("No qprocess support", SkipAll);
+#elif defined(Q_OS_MACOS)
+    QSKIP("QTBUG-59936: Times out on macOS", SkipAll);
 #else
     rememberKey("readonly_segfault");
     // ### on windows disable the popup somehow