Make type error detection less specific

[eernstg]

The treatment of type errors in Dart is about to change slightly. Currently there is a distinction between TypeError and CastError, but in the future we plan to stop making this distinction. Cf. dart-lang/language#787.

In order to avoid having failures due to overly specific expectations about the error thrown in various tests, we should adjust the checkTypeError in https://github.com/dart-lang/co19/blob/45dcc9d4a34f008af14f8b881ac2b85f084d46f0/Utils/dynamic_check.dart to be

checkTypeError(f()) {
  Expect.throws(f, (e) => e is TypeError || e is CastError,
      'Type error should be thrown');
}

and use this in order to verify that a type error occurs, rather than checking specifically for a TypeError or a CastError.

[eernstg]

I can see that checkTypeError is now applying the less specific check. But how about all the usages?

sdk/tests/co19/src((def1183ba...))$ dgrep '\bTypeError\b' | wc -l
6743
sdk/tests/co19/src((def1183ba...))$ dgrep '\bCastError\b' | wc -l
36

[sgrekhov]

@eernstg thank you for pointing. Fixed

[eernstg]

@sgrekhov, thank you for fixing a lot of code in a few hours! ;-)