[dart:core] Update num `operator ==` parameter type in NNBD fork
[dart:core] Update num `operator ==` parameter type in NNBD fork

Should the type agree with operator on Object?

Change-Id: I4a0257cec08a92898cb302c34e66a2fda4cfce6f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/125728
Reviewed-by: Leaf Petersen <9bef692239b5f624cec8e2cd5249ab1939a377aa@google.com>
Commit-Queue: Nicholas Shahan <03847abd2d8aadfe859ecb98095a31f9f515dc47@google.com>

dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk