[jdk21u-dev] RFR: 8322166: Files.isReadable/isWritable/isExecutable expensive when file does not exist

[Todd V. Jonker]

Clean backport of a performance fix, originally authored by @bplb and reviewed by @AlanBateman 

Test suites run on linux-x86_64-server-release:
- [x] tier1
- [x] jdk/java/nio

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Commit messages:
 - Backport 51be857f3cafa23eb7cd73e5fe3db17e6d01684c

Changes: https://git.openjdk.org/jdk21u-dev/pull/926/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=926&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322166
  Stats: 126 lines in 6 files changed: 76 ins; 28 del; 22 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/926.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/926/head:pull/926

PR: https://git.openjdk.org/jdk21u-dev/pull/926