tst_QLocalSocket::processConnections: remove QSKIP

on macOS, the test seems to be stable nowadays.

Task-number: QTBUG-39986
Change-Id: I18430c3feb27a5bee5474e1eb95f7d89b25f00a9
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

tests/auto/network/socket/qlocalsocket/tst_qlocalsocket.cpp

@@ -962,9 +962,6 @@ void tst_QLocalSocket::processConnection()
 #if !QT_CONFIG(process)
     QSKIP("No qprocess support", SkipAll);
 #else
-#ifdef Q_OS_MAC
-    QSKIP("The processConnection test is unstable on Mac. See QTBUG-39986.");
-#endif
 
 #ifdef Q_OS_WIN
     const QString exeSuffix = QStringLiteral(".exe");