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.cpp

@@ -45,11 +45,11 @@ ITestParser *CatchFramework::createTestParser()
     return new CatchTestParser(this);
 }
 
-TestTreeItem *CatchFramework::createRootNode()
+ITestTreeItem *CatchFramework::createRootNode()
 {
     return new CatchTreeItem(this,
                              QCoreApplication::translate("CatchFramework", "Catch Test"),
-                             QString(), TestTreeItem::Root);
+                             QString(), ITestTreeItem::Root);
 }
 
 } // namespace Internal