RFR: 8344256: Clean up obsolete code in java.desktop/share/classes/sun/awt/datatransfer/DataTransferer.java

[Phil Race]

Clean up obsolete code in DataTransferer.java
The main aim here was to get rid of ProtectionDomain and other SM related usage.

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Commit messages:
 - 8344256

Changes: https://git.openjdk.org/jdk/pull/22381/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22381&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344256
  Stats: 103 lines in 1 file changed: 0 ins; 98 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/22381.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22381/head:pull/22381

PR: https://git.openjdk.org/jdk/pull/22381