CMakePM: Start integrating ctest

Gather some more information of a CMake based project to be
able to provide this later on to the AutoTest plugin.

Task-number: QTCREATORBUG-23332
Change-Id: I2beaf0a6456d57871dcf65832f0a79f37fe5fddc
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/cmakeprojectmanager/cmakeprocess.cpp

@@ -203,6 +203,7 @@ void CMakeProcess::handleProcessFinished(int code, QProcess::ExitStatus status)
     } else if (code != 0) {
         msg = tr("CMake process exited with exit code %1.").arg(code);
     }
+    m_lastExitCode = code;
 
     if (!msg.isEmpty()) {
         Core::MessageManager::write(msg);