Valgrind: Make the (threaded) parser a proper member of the runner

Simplifies user code, and it was only ever used in a 1:1 relation,
even in the tests.

Change-Id: I3ce4fc83a361aceb730c05420efdb4ea52d37cda
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/valgrind/valgrindtestrunnertest.h

@@ -33,7 +33,6 @@
 
 namespace Valgrind {
 
-namespace XmlProtocol { class ThreadedParser; }
 class ValgrindRunner;
 
 namespace Test {
@@ -72,7 +71,6 @@ private slots:
 private:
     QString runTestBinary(const QString &binary, const QStringList &vArgs = QStringList());
 
-    XmlProtocol::ThreadedParser *m_parser = nullptr;
     ValgrindRunner *m_runner = nullptr;
     QList<QByteArray> m_logMessages;
     QList<XmlProtocol::Error> m_errors;