AutoTest: Introduce ITestTool

Preparation for separating handling of code based and
build system based tests.

Task-number: QTCREATORBUG-23332
Change-Id: I490af5f3157fd4a8cd07d976cdfd9e4503ade97b
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/catch/catchframework.h

@@ -42,7 +42,7 @@ public:
 
 protected:
     ITestParser *createTestParser() override;
-    TestTreeItem *createRootNode() override;
+    ITestTreeItem *createRootNode() override;
 
 private:
     ITestSettings * testSettings() override { return &m_settings; }