TestResult: Devirtualize the class - part 2 of 5

Step 2 - implement findTestItemHook.

Change-Id: Iabc843740343e549f79b02f74f94f5b1b4713af3
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/testresult.cpp

@@ -27,6 +27,8 @@ const QString TestResult::outputString(bool selected) const
 
 const ITestTreeItem *TestResult::findTestTreeItem() const
 {
+    if (m_hooks.findTestItem)
+        return m_hooks.findTestItem(*this);
     return nullptr;
 }