This is a part of [1] and a continuation of [2].
- Make typed data implementation file a library, to allow importing it
in `dart:convert` patch.
- Make SIMD implementation file a library, to allow importing it from
the typed data library.
- Make typed data implementation classes internally public (available in
other `dart:...` libraries).
- Relax `mayDefineRestrictedType` to allow implementing restricted types
anywhere in the standard library implementation.
[1]: https://dart-review.googlesource.com/c/sdk/+/330121
[2]: https://dart-review.googlesource.com/c/sdk/+/330781
Change-Id: I70bc6869a20fd2479bee081cfceef27d6de19974
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/330783
Commit-Queue: Ömer Ağacan <omersa@google.com>
Reviewed-by: Jackson Gardner <jacksongardner@google.com>
ce9e332bb1