Backport new version of buffer size fixes

[andyleiserson]

Applies #7911 to the firefox-141 branch. Since the original version of the change was not reverted on this branch, the commit that undoes the reversion is not included. The "fix for destroyed resource errors" commit is also not included, because it only makes sense with other error reporting changes that landed on trunk after the branch point.

Testing
Enables a few CTS tests.

Squash or Rebase? Rebase

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.