RFR: 8266839: Enable pandoc on macosx-aarch64 at Oracle

[Mikael Vidstedt]

Enabling pandoc on macosx-aarch64 at Oracle to produce man pages etc.

Testing:

* Passes tier1
* Verified that the product bundle includes man pages as expected
* Sampling a few of the man pages they look as expected

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Commit messages:
 - 8266839: Enable pandoc on macosx-aarch64

Changes: https://git.openjdk.java.net/jdk/pull/6650/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6650&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266839
  Stats: 13 lines in 1 file changed: 11 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6650.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6650/head:pull/6650

PR: https://git.openjdk.java.net/jdk/pull/6650