Remove dead Python code in binding generating code

Fixes #6956

components/script/dom/bindings/codegen/Configuration.py

@@ -4,8 +4,6 @@
 
 from WebIDL import IDLInterface
 
-autogenerated_comment = "/* THIS FILE IS AUTOGENERATED - DO NOT EDIT */\n"
-
 
 class Configuration:
     """
@@ -344,17 +342,6 @@ def getTypesFromDescriptor(descriptor):
     return types
 
 
-def getFlatTypes(types):
-    retval = set()
-    for type in types:
-        type = type.unroll()
-        if type.isUnion():
-            retval |= set(type.flatMemberTypes)
-        else:
-            retval.add(type)
-    return retval
-
-
 def getTypesFromDictionary(dictionary):
     """
     Get all member types for this dictionary