Add qt-widgets-app unit test

Change-Id: I502075f79d4abf6bd5c0d2080b2f543116499ace
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>

plugins/clangstaticanalyzer/unit-tests/qt-widgets-app/mainwindow.cpp

@@ -0,0 +1,14 @@
+#include "mainwindow.h"
+#include "ui_mainwindow.h"
+
+MainWindow::MainWindow(QWidget *parent) :
+    QMainWindow(parent),
+    ui(new Ui::MainWindow)
+{
+    ui->setupUi(this);
+}
+
+MainWindow::~MainWindow()
+{
+    delete ui;
+}