feat(unstable): repurpose --unstable-detect-cjs to attempt loading more modules as cjs (#27094)

This resurrects the `--unstable-detect-cjs` flag (which became stable),
and repurposes it to attempt loading .js/.jsx/.ts/.tsx files as CJS in
the following additional scenarios:

1. There is no package.json
1. There is a package.json without a "type" field

Also cleans up the implementation of this in the LSP a lot by hanging
`resolution_mode()` off `Document` (didn't think about doing that until
now).

cli/lsp/diagnostics.rs

@@ -1707,7 +1707,6 @@ mod tests {
         documents: Arc::new(documents),
         assets: Default::default(),
         config: Arc::new(config),
-        is_cjs_resolver: Default::default(),
         resolver,
       },
     )