RFR: 8287843: File::getCanonicalFile doesn't work for \\?\C:\ style paths DOS device paths [v8]

[Brian Burkhalter]

> In the Windows implementation of java.io.File.getCanonicalPath, strip any long path or UNC prefix before canonicalizing the remainder of the pathname.

Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 11 additional commits since the last revision:

 - 8287843: Change tests as suggested in review
 - Merge
 - 8287843: Remove unused constant and method from WindowsPrefixes test
 - 8287843: remove stripLongOrUNCPrefix() except in normalize()
 - 8287843: Strip prefix in more methods; remove bad test case
 - 8287843: Add WindowsPrefixes test
 - 8287843: Convert GetAbsolutePath and IsAbsolute tests to JUnit and add some test cases
 - 8287843: Move prefix stripping to separate method; add to isAbsolute
 - 8287843: Move \\?\ prefix stripping to resolve(File)
 - 8287843: Handle "\\?\UNC"; add bad paths to test
 - ... and 1 more: https://git.openjdk.org/jdk/compare/3ed19459...2f313185

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15603/files
  - new: https://git.openjdk.org/jdk/pull/15603/files/a43f7276..2f313185

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15603&range=07
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15603&range=06-07

  Stats: 807994 lines in 5961 files changed: 173684 ins; 518195 del; 116115 mod
  Patch: https://git.openjdk.org/jdk/pull/15603.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15603/head:pull/15603

PR: https://git.openjdk.org/jdk/pull/15603