[jdk11u-dev] RFR: 8217032: Check pandoc capabilities in configure

[George Adams]

Backport applies cleanly other than the [following two lines](https://github.com/openjdk/jdk/commit/4f45b5f9739e5a5e7d1c4f80da9c42e0d77dd0bf#diff-b2617a3c263800cf342a5a17bf7bd8dde629a6445bee9eca59c40686dca7932bR621-R622) not being present in JDK11u.

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Commit messages:
 - Backport 4f45b5f9739e5a5e7d1c4f80da9c42e0d77dd0bf

Changes: https://git.openjdk.org/jdk11u-dev/pull/1352/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1352&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8217032
  Stats: 34 lines in 3 files changed: 32 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1352.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1352/head:pull/1352

PR: https://git.openjdk.org/jdk11u-dev/pull/1352