RFR: 8320918: Fix errors in the built-in Catalog implementation

[Joe Wang]

Fix errors in the built-in Catalog implementation, specifically:
    -- incorrect case in the property name as defined in the CSR (https://bugs.openjdk.org/browse/JDK-8306056)
    -- tests needed to be updated accordingly
    -- jaxp.properties updated with documentation for the new properties
    
Tests: passed after the update.

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Commit messages:
 - 8320918: Fix errors in the built-in Catalog implementation

Changes: https://git.openjdk.org/jdk/pull/16862/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16862&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320918
  Stats: 50 lines in 6 files changed: 38 ins; 4 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/16862.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16862/head:pull/16862

PR: https://git.openjdk.org/jdk/pull/16862