QmlProfiler: Pimpl QmlProfilerPlugin class a bit more

... to be able to remove an unneeded use of the global object pool.

Plus some code cosmetics.

Change-Id: Ifdb0ff9cd40820a34a8951563402a50a594e4fdd
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/qmlprofiler/qmlprofilertool.cpp

@@ -131,8 +131,8 @@ public:
     bool m_toolBusy = false;
 };
 
-QmlProfilerTool::QmlProfilerTool(QObject *parent)
-    : QObject(parent), d(new QmlProfilerToolPrivate)
+QmlProfilerTool::QmlProfilerTool()
+    : d(new QmlProfilerToolPrivate)
 {
     setObjectName(QLatin1String("QmlProfilerTool"));