RFR: 8315485: (fs) Move java/nio/file/Path/Misc.java tests into java/nio/file/Path/PathOps.java

[Brian Burkhalter]

In the `java/nio/file/Path` tests, add to `PathOps` tests equivalent to those in `Misc` and then remove the latter.

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Commit messages:
 - 8315485: Remove Misc.java
 - 8315485: (fs) Move java/nio/file/Path/Misc.java tests into java/nio/file/Path/PathOps.java

Changes: https://git.openjdk.org/jdk/pull/15572/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15572&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315485
  Stats: 154 lines in 2 files changed: 63 ins; 88 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15572.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15572/head:pull/15572

PR: https://git.openjdk.org/jdk/pull/15572