RFR: 8360028: (fs) Path.relativize throws StringIndexOutOfBoundsException (win)

[Brian Burkhalter]

Ignore empty name elements in `WindowsPath.normalize()`.

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Commit messages:
 - 8360028: (fs) Path.relativize throws StringIndexOutOfBoundsException (win)

Changes: https://git.openjdk.org/jdk/pull/26080/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26080&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360028
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26080.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26080/head:pull/26080

PR: https://git.openjdk.org/jdk/pull/26080