CFE reports an incorrect old primitive equality error on co19/Language/Expressions/Constants/equals_expression_t03

[munificent]

We're rolling a bunch of a co19 updates in the Dart SDK. Most of the changes are related to patterns, but there are some related to the changes to constant equality. Prior to Dart 3.0, an == expression was only constant if the LHS was one of a fixed list of types. In 3.0, we loosened that to allow any type that has primitive equality (i.e. doesn't override ==).

The test co19/Language/Expressions/Constants/equals_expression_t03 has been updated to test that behavior, but it looks like CFE isn't implementing it yet and still reports an error based on the old constant equality rule.