RFR: 8370633: Remove dead code for Windows file path canonicalization functions

[Iris Clark]

On Fri, 24 Oct 2025 19:21:38 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Remove the unused, vestigial functions `wcanonicalizeWithPrefix` and `Java_java_io_WinNTFileSystem_canonicalizeWithPrefix0`. With this change, the build in the CI succeeds on Windows.

Marked as reviewed by iris (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27981#pullrequestreview-3381172171