Adapt to LLVM 13

ApiExtractor/TestEnum::testAnonymousEnum() qt.shiboken: enum 'A::A1' is specified in typesystem, but not declared.
QWARN  : TestEnum::testAnonymousEnum() qt.shiboken: enum 'A::isThis' is specified in typesystem, but not declared.
QWARN  : TestEnum::testAnonymousEnum() qt.shiboken: enum 'Global0' is specified in typesystem, but not declared.

  File "sources/shiboken6/tests/samplebinding/enum_test.py", line 114, in testAnonymousClassEnums
    self.assertEqual(SampleNamespace.AnonymousClassEnum_Value0, 0)
AttributeError: type object 'sample.SampleNamespace' has no attribute 'AnonymousClassEnum_Value0'


    self.assertEqual(sample.AnonymousGlobalEnum_Value0, 0)
AttributeError: module 'sample' has no attribute 'AnonymousGlobalEnum_Value0'

  File "sources/shiboken6/tests/samplebinding/enumfromremovednamespace_test.py", line 50, in testEnumPromotedToGlobal
    sample.RemovedNamespace1_AnonymousEnum_Value0
AttributeError: module 'sample' has no attribute 'RemovedNamespace1_AnonymousEnum_Value0'

  File "sources/shiboken6/tests/samplebinding/enumfromremovednamespace_test.py", line 76, in testEnumPromotedToUpperNamespace
    sample.UnremovedNamespace.RemovedNamespace3_AnonymousEnum_Value0
AttributeError: type object 'sample.UnremovedNamespace' has no attribute 'RemovedNamespace3_AnonymousEnum_Value0'