[jdk11u-dev] RFR: Merge jdk11u:master

[Goetz Lindenmaier]

Merge build tag 11.0.18+9 from jdk11u to jdk11u-dev

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Commit messages:
 - Merge
 - 8280890: Cannot use '-Djava.system.class.loader' with class loader in signed JAR

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/jdk11u-dev/pull/1616/files
  Stats: 183 lines in 4 files changed: 139 ins; 28 del; 16 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1616.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1616/head:pull/1616

PR: https://git.openjdk.org/jdk11u-dev/pull/1616