RFR: 8353009: Document target selection flag for Windows AArch64 builds [v3]

[Saint Wesonga]

> The target selection configuration flag for Windows AArch64 should be added to the build documentation for improved discoverability and completeness.

Saint Wesonga has updated the pull request incrementally with one additional commit since the last revision:

  Add instructions for a native Windows AArch64 build

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24267/files
  - new: https://git.openjdk.org/jdk/pull/24267/files/8cb94d9b..ce4a5914

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24267&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24267&range=01-02

  Stats: 18 lines in 2 files changed: 18 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24267.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24267/head:pull/24267

PR: https://git.openjdk.org/jdk/pull/24267