[turbopack] Remove some unnecessary awaits now that FileSystemPath is synchronously available. (#81090)
### Remove some unnecessary awaits now that FileSystemPath is synchronously available.
### What?
* Remove `async` from `ContextCondition::matches` simplifying the implementation and eliminating a bunch of temporary allocations
* Remove some unnecessary FileSystemPath clones
* Remove recursion from `resolve::base_options` this function really just wants the FileSystem::root so require that instead
* Share the same same `cell` for most of the node externals
### Why?
Noticed this while reviewing the `resovle` codebase. I expect them to by negligible perf wins, but wins nontheless