WASI FS does not work with latest NodeJS versions

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WASI-based FS implementation does not work with latest NodeJS versions.

Previously, operations accepting paths worked with absolute path as long as path's prefix was matching a directory corresponding to the fd. In other words, if there was a file descriptor corresponding to the /tmp directory, operations working with path were accepting absolute paths like /tmp/foo.

After nodejs/node#59791 it's no longer the case, an attempt to pass an absolute path will end with the notcapable error.

I tested the following versions:

• 22.20.0
• 25.0.0

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Preview 1's docs says only that path_open's path-parameter has to be relative (https://github.com/WebAssembly/WASI/blob/9ea0e7534f46f0c39f28b386fa2becf00923a857/legacy/preview1/witx/wasi_snapshot_preview1.witx#L368), and does not explicitly specify it for other functions. In the second preview, all functions accept only relative paths (but the error has to be different: https://github.com/WebAssembly/wasi-filesystem/blob/971b11617b50e7496bea85f36e60141bda172964/wit/types.wit#L20).

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The behavior was changed in uvwasi: nodejs/uvwasi#270