Debugger: Allow explicitly marking of non-Python commands again

This conceptually reverts part of a61b6dfc.

Task-number: QTCREATORBUG-17594
Change-Id: I9ff72a027838a20039f217ed0d669b6c45bc2acf
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/debugger/debuggerengine.h

@@ -208,6 +208,7 @@ public:
         LosesChild = DebuggerCommand::LosesChild,
         RebuildBreakpointModel = DebuggerCommand::RebuildBreakpointModel,
         InUpdateLocals = DebuggerCommand::InUpdateLocals,
+        NativeCommand = DebuggerCommand::NativeCommand,
         Silent = DebuggerCommand::Silent
     };