Fix diff parser: error dedents in between nodes should be ignored for now when copying

parso/python/diff.py

@@ -617,6 +617,8 @@ class _NodesTree(object):
                 # Endmarkers just distort all the checks below. Remove them.
                 break
 
+            if node.type == 'error_leaf' and node.token_type == 'ERROR_DEDENT':
+                break
             # TODO this check might take a bit of time for large files. We
             # might want to change this to do more intelligent guessing or
             # binary search.