e1f972cb86
This is a reland of eafe8b04c0
Original change's description:
> [dartdevc] Making multi-root paths consistently use url-relative path separators.
>
> Fixes #38802
>
> Change-Id: I8b0e9525d0be9a00b9189d673f2881d432de4b66
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/122419
> Auto-Submit: Mark Zhou <markzipan@google.com>
> Reviewed-by: Jake Macdonald <jakemac@google.com>
> Commit-Queue: Mark Zhou <markzipan@google.com>
Change-Id: Ie5a6cb2c73ef1411dd73e12109bd406908aa5fb3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/122660
Reviewed-by: Jake Macdonald <jakemac@google.com>
Commit-Queue: Mark Zhou <markzipan@google.com>