May make the tests less flaky

python3/vimspector/debug_session.py

@@ -218,6 +218,7 @@ class DebugSession( object ):
     if self._connection:
       self._connection.OnData( data )
 
+
   def OnServerStderr( self, data ):
     self._logger.info( "Server stderr: %s", data )
     if self._outputView:

python3/vimspector/output.py

@@ -103,7 +103,7 @@ class OutputView( object ):
         if 'E516' not in e:
           raise
 
-    self._buffers.clear()
+    self._buffers = {}
 
   def _ShowOutput( self, category ):
     utils.JumpToWindow( self._window )