RFR: 8323740: java.lang.ExceptionInInitializerError when trying to load XML classes in wrong order

[Liam Miller-Cushon]

Please consider this fix for [JDK-8323740](https://bugs.openjdk.org/browse/JDK-8323740), which avoids an `ExceptionInInitializerError` in the class initializer of `XMLDocumentFragmentScannerImpl` and other classes that have a circular dependency on `jdk.xml.internal.JdkXmlUtils`. The change breaks the cycle by moving some initialization out of the class initializer of `JdkXmlUtils`.

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

Commit messages:
 - 8323740: java.lang.ExceptionInInitializerError when trying to load XML classes in wrong order

Changes: https://git.openjdk.org/jdk/pull/22803/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22803&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323740
  Stats: 46 lines in 2 files changed: 44 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/22803.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22803/head:pull/22803

PR: https://git.openjdk.org/jdk/pull/22803