path/filepath: add Localize

[qiulaidongfeng]

Implemented filepath.Localize using internal/safefilepath.FromFS.

Fixes #57151

Change-Id: I98c6a211d77fa5c8733306b5ef39950bae07fb5c

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[gopherbot]

Message from Gopher Robot:

Patch Set 1:

(1 comment)

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[gopherbot]

Message from qiulaidongfeng:

Patch Set 2:

(1 comment)

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After addressing review feedback, remember to publish your drafts!

[gopherbot]

This PR (HEAD: 766cdf2) has been imported to Gerrit for code review.

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