e6a313568c
In order to support this, adds necessary changes to conversion functions (including cast-lists) and makes JSArrayImpl a generic type. CoreLibraryReviewExempt: Backend-specific library changes. Change-Id: I58bcfb67ef21c90be5e25735757d780aac52dc23 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/337923 Reviewed-by: Sigmund Cherem <sigmund@google.com> Commit-Queue: Srujan Gaddam <srujzs@google.com>