RFR: 8294526: sun/security/provider/SubjectCodeSource.java no longer referenced

[Ryan Wallace]

SubjectCodeSource is no longer used, Class should be deleted and all references updated

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Commit messages:
 - Merge branch 'master' into 8294526
 - Merge branch 'master' into 8294526
 - 8294526: SubjectCodeSource is no longer referenced
 - Merge branch 'master' into 8294526
 - Merge branch 'openjdk:master' into 8294526
 - 8294526: SubjectCodeSource is no longer used, removing class and all references

Changes: https://git.openjdk.org/jdk/pull/10550/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10550&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294526
  Stats: 391 lines in 2 files changed: 3 ins; 388 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10550.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10550/head:pull/10550

PR: https://git.openjdk.org/jdk/pull/10550