Debugger: Fix use of GDB's own pretty printers

... with newer versions of GDB.

Looks like their internal behavior changed (again...)

Task-number: QTCREATORBUG-16758
Change-Id: Ic3a092091bac73df92a3a9f33ab863e4b6ece9b4
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: hjk <hjk@qt.io>

share/qtcreator/debugger/gdbbridge.py

@@ -168,7 +168,10 @@ class PlainDumper:
         self.typeCache = {}
 
     def __call__(self, d, value):
-        printer = self.printer.gen_printer(value)
+        try:
+            printer = self.printer.gen_printer(value)
+        except:
+            printer = self.printer.invoke(value)
         lister = getattr(printer, "children", None)
         children = [] if lister is None else list(lister())
         d.putType(self.printer.name)