AutoTest: Allow framework specific tool tip on settings

The grouping checkbox enables grouping, but frameworks can have
more grouping modes than the default implementation.
Allow frameworks to provide its own tool tip for the checkbox
on the general settings page.

Change-Id: I0515e542284491a669ef33820104a32074ecf885
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/itestframework.h

@@ -71,7 +71,8 @@ public:
     void setActive(bool active) { m_active = active; }
     bool grouping() const { return m_grouping; }
     void setGrouping(bool group) { m_grouping = group; }
-
+    // framework specific tool tip to be displayed on the general settings page
+    virtual QString groupingToolTip() const { return QString(); }
 protected:
     virtual ITestParser *createTestParser() const = 0;
     virtual TestTreeItem *createRootNode() const = 0;