message: Fix a test whose output changed.
  A previous commit fixed an issue with our AST generation where
  we were outputting enum decls incorrectly.  But we forgot to
  update the test output.  This patch updates the test output
  accordingly.
diff: @@ -304,8 +304,8 @@ constexpr References ReferencesInstance;
  // CHECK: | |-FieldDecl {{.*}} o 'long long'
  // CHECK: | `-FieldDecl {{.*}} p 'int [5]'
  // CHECK: |-EnumDecl {{.*}} EnumType
  -// CHECK: | |-EnumConstantDecl {{.*}} A 'unsigned int'
  -// CHECK: | `-EnumConstantDecl {{.*}} B 'unsigned int'
  +// CHECK: | |-EnumConstantDecl {{.*}} A 'EnumType'
  +// CHECK: | `-EnumConstantDecl {{.*}} B 'EnumType'
  // CHECK: |-CXXRecordDecl {{.*}} struct DerivedClass definition
  // CHECK: | |-public 'BaseClass<int>'
  // CHECK: | `-FieldDecl {{.*}} DerivedMember 'int'
  