Debugger: Fix async tooltip handling

For now, only the gdb engine can handle complex tooltips
requiring async re-evaluation, cdb and lldb will show
and expand only items that are available in the Locals view.

This patch disables also the save/restore feature for
pinned tooltips.

Task-number: QTCREATORBUG-13255
Task-number: QTCREATORBUG-13052
Change-Id: Ic25616fede0f5c4343a92b631f01e60bfc5e9d81
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/gdb/gdbengine.h

@@ -298,7 +298,6 @@ private: ////////// View & Data Stuff //////////
 
     void selectThread(ThreadId threadId);
     void activateFrame(int index);
-    void resetLocation();
 
     //
     // Breakpoint specific stuff
@@ -469,7 +468,6 @@ protected:
     void showExecutionError(const QString &message);
 
     static QByteArray tooltipIName(const QString &exp);
-    DebuggerToolTipContext m_toolTipContext;
 
     // For short-circuiting stack and thread list evaluation.
     bool m_stackNeeded;