Update some other methods to be more performant than the default
inherited from `MapMixin`.
Change argument validation to `map.[]=`, `map.putIfAbsent` and `set.add`
checks that the key/element is allowed by the `compare` function.
Previously the map methods just checked `key != null` (which was wrong),
and compare did nothing special, both just relied on the `splay` call
doing a `compare` call. That was not true for an empty map, which means
that you could add a key/element which wasn't a valid comparable,
as long as you did it as the *first* key/element.
That is now caught.
Bug: https://github.com/dart-lang/sdk/issues/45296
Change-Id: I8ba49a7892ed27daa4434f5fb7be3e777ef32bc9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/190883
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Lasse Reichstein Holst Nielsen