RFR: 8259637: java.io.File.getCanonicalPath() returns different values for same path

[Brian Burkhalter]

Modify the `collapse()` function to remove each instance of ".." when the path is absolute and there is no preceding name.

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Commit messages:
 - 8259637: java.io.File.getCanonicalPath() returns different values for same path

Changes: https://git.openjdk.org/jdk/pull/17089/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17089&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8259637
  Stats: 44 lines in 2 files changed: 37 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17089.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17089/head:pull/17089

PR: https://git.openjdk.org/jdk/pull/17089