Debugger: Move some 'mixed native' code to DumperBase

Prepares reuse in LLDB.

Change-Id: I2238a94937411b80a9ec84ab738aba2146bba50e
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/debugger/gdb/gdbengine.h

@@ -196,6 +196,7 @@ private: ////////// Gdb Command Management //////////
     // watch model updates before everything is finished.
     void flushCommand(const GdbCommand &cmd);
 protected:
+    void runCommand(const DebuggerCommand &command);
     void postCommand(const QByteArray &command,
                      GdbCommandFlags flags,
                      GdbCommandCallback callback = 0,