RFR: 8341551: Revisit jdk.internal.loader.URLClassPath.JarLoader after JEP 486 [v4]

[Jaikiran Pai]

> Can I please get a review of this change which proposes to address https://bugs.openjdk.org/browse/JDK-8341551? 
> 
> The primary work in this PR is the specification of the previously existing `sun.misc.URLClassPath.disableJarChecking` system property and how the internal implementation of `java.net.URLClassLoader` treats it. The complete details about this property is available in the CSR for this change here https://bugs.openjdk.org/browse/JDK-8345394.
> 
> A new jtreg test has been introduced to exercise the usage of this system property.

Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:

  Roger's suggestion - reduce "if" blocks

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22545/files
  - new: https://git.openjdk.org/jdk/pull/22545/files/6c153ea8..c185c65e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22545&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22545&range=02-03

  Stats: 4 lines in 1 file changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22545.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22545/head:pull/22545

PR: https://git.openjdk.org/jdk/pull/22545