[jdk17] RFR: 8266345: (fs) Custom DefaultFileSystemProvider security related loops

[Sean Mullan]

Please review this fix to use the platform's default file system to avoid recursive policy initialization
issues when a SecurityManager is enabled and the VM is configured to use a custom file system provider.

-------------

Commit messages:
 - 8266345: (fs) Custom DefaultFileSystemProvider security related loops

Changes: https://git.openjdk.java.net/jdk17/pull/232/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=232&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266345
  Stats: 30 lines in 3 files changed: 28 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/232.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/232/head:pull/232

PR: https://git.openjdk.java.net/jdk17/pull/232