Debugger: Make GDBMI parser more robust

Task-number: QTCREATORBUG-25745
Change-Id: I1a4f89fc72433548d44461c3c7c02bd53708d12d
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/debugger/debuggerprotocol.h

@@ -131,7 +131,7 @@ public:
 
     QChar current() const { return *from; }
     bool isCurrent(QChar c) const { return *from == c; }
-    bool isAtEnd() const { return from == to; }
+    bool isAtEnd() const { return from >= to; }
 
     void advance() { ++from; }
     void advance(int n) { from += n; }