Towards https://github.com/flutter/flutter/issues/162846.
Removes all of the unsound host artifacts, and then uses their name for
the sound artifacts.
That is, for something like `webPlatformDDCKernelDill`, this PR:
- Changes the web GN builders to only emit the sound SDK, without the
`-sound` suffixes
- Deletes `webPlatformDDCKernelDill` and all usages of it (implicitly
unsound, and unused).
- Renames `webPlatformDDCKernelSoundDill` to `webPlatformDDCKernelDill`.
No user impact expected, as there was no way to use the unsound
artifacts from the Flutter tool.
b728c4c06a