Fix a deadlock when closing Creator while loading a project

Replace the call to SynchronousProcess::run() by asynchronous
call that invokes a process.

This change may be tested by applying the additional patch
mentioned in QTCREATORBUG-25385 description.

Don't call the SynchronousProcess::run() from the main thread when
the Quit event was already scheduled for qApp, since the Quit event
will get removed from the awaiting queue by a call to
QEventLoop::exec().

Fixes: QTCREATORBUG-25385
Change-Id: I8af39552443bfa9b3af6e31ddce85a01b91bbbd8
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildsystem.h

@@ -35,6 +35,8 @@
 #include <utils/fileutils.h>
 #include <utils/temporarydirectory.h>
 
+#include <QFutureSynchronizer>
+
 namespace ProjectExplorer { class ExtraCompiler; }
 
 namespace CppTools {
@@ -181,6 +183,7 @@ private:
     // CTest integration
     QString m_ctestPath;
     QList<ProjectExplorer::TestCaseInfo> m_testNames;
+    QFutureSynchronizer<QByteArray> m_futureSynchronizer;
 };
 
 } // namespace Internal