RFR: 8343150: Remove URLClassLoader.getPermissions after JEP 486 integration [v2]

[Jaikiran Pai]

> Can I please get a review of this change which removes the `getPermissions()` method from the `URLClassLoader`? This addresses https://bugs.openjdk.org/browse/JDK-8343150.
> 
> With the SecurityManager implementation removed through JEP 486, this method of the `URLClassLoader` is no longer relevant.
> 
> No new tests have been added. tier1 and tier2 testing is currently in progress.

Jaikiran Pai 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 three additional commits since the last revision:

 - update the specification of java.security.SecureClassLoader.getPermissions()
 - merge latest from master branch
 - 8343150: Remove URLClassLoader.getPermissions after JEP 486 integration

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22179/files
  - new: https://git.openjdk.org/jdk/pull/22179/files/e5d8ee3b..d6220b19

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22179&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22179&range=00-01

  Stats: 49315 lines in 339 files changed: 21641 ins; 26435 del; 1239 mod
  Patch: https://git.openjdk.org/jdk/pull/22179.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22179/head:pull/22179

PR: https://git.openjdk.org/jdk/pull/22179