Debugger: Make some LLDB warning not break output format

Dumper.warn() tries to interleave the message with an
ongoing report, whereas the global warn prints directly,
possibly breaking the report parsing.

Change-Id: If753773d5eedf98a489f155d46d2911e04059461
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

share/qtcreator/debugger/lldbbridge.py

@@ -934,7 +934,7 @@ class Dumper(DumperBase):
 
     def putSubItem(self, component, value, tryDynamic=True):
         if not value.IsValid():
-            warn("INVALID SUBITEM: %s" % value.GetName())
+            self.warn("INVALID SUBITEM: %s" % value.GetName())
             return
         with SubItem(self, component):
             self.putItem(value, tryDynamic)