[jdk11u-dev] RFR: 8280373: Update Xalan serializer / SystemIDResolver to align with JDK-8270492

[Andrew John Hughes]

Hi all,

This pull request contains a backport of commit [c180070c](https://github.com/openjdk/jdk/commit/c180070cb59b8e075376ae913c5db9a4ed868303) from the [openjdk/jdk](https://git.openjdk.java.net/jdk) repository.

The commit being backported was authored by Matthias Baesken on 26 Jan 2022 and was reviewed by Yuri Nesterenko and Joe Wang.

JDK-8270492 was a security fix in the January security update which was backported to 8u, 11u & 17u. This fix synchronises `src/java.xml/share/classes/com/sun/org/apache/xml/internal/serializer/utils/SystemIDResolver.java` to match the change in `src/java.xml/share/classes/com/sun/org/apache/xml/internal/utils/SystemIDResolver.java` made in JDK-8270492. The fix has already been backported to 17u.

Thanks!

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Commit messages:
 - Backport c180070cb59b8e075376ae913c5db9a4ed868303

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/1008/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1008&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280373
  Stats: 5 lines in 1 file changed: 2 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1008.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1008/head:pull/1008

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1008