[jdk11u-dev] RFR: 8287202: GHA: Add macOS aarch64 to the list of default platforms for workflow_dispatch event

[Christoph Langer]

This is a backport of https://bugs.openjdk.java.net/browse/JDK-8287202 to 11u-dev.
I had to resolve manually since the Windows arm64 port is not in 11u.

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Commit messages:
 - Backport f7a37f58862d08adbf8fb141bf43c362bda7fd16

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/1107/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1107&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8287202
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1107.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1107/head:pull/1107

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1107