[co19] Roll co19 to 5f2a1632af9509358d1325e546f47d3a0a22b912

2026-08-28 sgrekhov22@gmail.com Fixes dart-lang/co19#4198. Fix typos in up_A26_t01.dart and up_A27_t01.dart (dart-lang/co19#4199)
2026-08-27 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for bounded type variable (dart-lang/co19#4195)
2026-08-27 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for function types (dart-lang/co19#4196)
2026-08-26 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for nullable types (dart-lang/co19#4194)
2026-08-25 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for OBJECT (dart-lang/co19#4193)
2026-08-25 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for NULL types (dart-lang/co19#4192)
2026-08-24 sgrekhov22@gmail.com dart-lang/co19#4173. Add tests for intersection types (dart-lang/co19#4191)

R=athom@google.com, eernst@google.com

Cq-Include-Trybots: luci.dart.try:analyzer-linux-release-try,dart2js-minified-linux-d8-try
Change-Id: I9f0a48a0c54ae131e618575860ad8bcb9a54531a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/542760
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Auto-Submit: Sergey Grekhov <sgrekhov22@gmail.com>
Commit-Queue: Alexander Thomas <athom@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>