RFR: 8361325: Refactor ClassLoaderExt [v2]

[Calvin Cheung]

> After the refactoring work done via [JDK-8280682](https://bugs.openjdk.org/browse/JDK-8280682), there are only three functions remaining in the ClassLoaderExt class. This RFE is to move those remaining functions into other classes so that the ClassLoaderExt class can be eliminated.
> 
> Testing: passed tiers 1 - 5.

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  @coleenp comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26110/files
  - new: https://git.openjdk.org/jdk/pull/26110/files/19942e19..4cbd71fc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26110&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26110&range=00-01

  Stats: 11 lines in 2 files changed: 5 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26110.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26110/head:pull/26110

PR: https://git.openjdk.org/jdk/pull/26110