internal/filepathlite: use host node.js function to parse path in wasm

[Zxilly]

wasm works on a number of different host platforms,
so specific implementations of path operations should be provided by the host platform.

Fixes #43768

[gopherbot]

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[gopherbot]

Message from Gopher Robot:

Patch Set 1:

(1 comment)

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[gopherbot]

This PR (HEAD: f490e6d) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/go/+/604695.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
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• The title and description of the GitHub PR are used to construct the final commit message.
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[gopherbot]

Message from Zxilly Chou:

Patch Set 2:

(1 comment)

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