fix(metro-config): Replace source-map snapshots for metro-transformer-worker with mappings tests

[kitten]

Why

• Closes ENG-10873
• This reverts the lock on @babel/generator@~7.20.5 to @babel/generator@^7.20.5 to allow upgrades past 7.21.0
  • This was previously put in place in feat(metro-config): add custom metro transform worker #25833 and this is a follow-up PR
• @babel/generator@7.21.0 shipped a fix that added names of “friendly call frames” to its source maps (feat: Generate sourcemaps of friendly call frames babel/babel#15022). This caused the source maps to change to include internal names for in-scope identifiers such as globalThis and _interopRequireDefault
  • This was a completely backwards-compatible change for us, but this was obscured by source map output being a little hard to read

When applied, this PR replaces our source map snapshots with tests that check exact identifiers in the input and output against their mappings and names.
This should make it easier to identify changes to the source maps and allow us to debug them more easily in the future.

A note has been added to any assertions in the tests that break when downgrading below 7.21.0, but for now, I haven't added any additional tests that account for this, since I'm not expecting us to downgrade to the lower version again, and to instead keep all @babel/* packages in @expo/metro-config upgraded in lockstep.

How

• All source-map snapshots for metro-transformer-worker have been deleted
• @jridgewell/trace-mapping has been added to parse the worker’s source maps (with a small converter function)
  • This is an alternative to the ubiquitous source-map package, and it’s also used in Babel. It avoids parsing source maps in wasm.
  • When adding source-map instead, we’d have to work around our virtual FS mock
• All source-map snapshots have been replaced with checks for both input and output identifiers against the actual source-maps
• Additional tests have been added to check for internal globals, which previously caused the source maps to break

Test Plan

Note: When testing this, placing the pinned version back to @babel/generator@~7.20.5 causes some name properties to be missing in the source-map output for injected globals, as expected.

Checklist

• Documentation is up to date to reflect these changes (eg: https://docs.expo.dev and README.md).
• Conforms with the Documentation Writing Style Guide
• This diff will work correctly for npx expo prebuild & EAS Build (eg: updated a module plugin).

[linear]

ENG-10873 Update babel/generator in metro-config

[EvanBacon]

yarn watch and yarn build produce different outputs in @expo/metro-config to support lazy loading. We could probably get rid of this in a future PR, but this is why the build results are all different. I'll open a ticket to remove this extra lazy loading.

[EvanBacon]

Be sure to add the changelog entry