QmlProfiler: Support local connections on Qt >= 5.6

This removes the need to receive messages from the application via
stderr. The "Connecting to socket" is still parsed, but only for
diagnostic purposes. If it doesn't arrive, the profiling will still
work.

Change-Id: I022691293da2a1e671ba1263bc76e4044bf1a5b7
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

src/plugins/analyzerbase/analyzerstartparameters.h

@@ -62,6 +62,7 @@ public:
     QString workingDirectory;
     QString sysroot;
     QString analyzerHost;
+    QString analyzerSocket;
     quint16 analyzerPort = 0;
 };