RFR: 8362598: [macos] Add tests for custom info plist files [v4]

[Alexander Matveev]

> - Added test for custom info plist to cover app image including embedded runtime and runtime installer.
> - Fixed bug in `writePList`. It was missing `writeStartDocument()/writeEndDocument()` and `DOCTYPE` should be full xml string.

Alexander Matveev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into JDK-8362598
 - 8362598: [macos] Add tests for custom info plist files [v4]
 - 8362598: [macos] Add tests for custom info plist files [v3]
 - 8362598: [macos] Add tests for custom info plist files [v2]
 - 8362598: [macos] Add tests for custom info plist files

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27509/files
  - new: https://git.openjdk.org/jdk/pull/27509/files/af103a66..267bd365

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27509&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27509&range=02-03

  Stats: 11234 lines in 552 files changed: 5424 ins; 2593 del; 3217 mod
  Patch: https://git.openjdk.org/jdk/pull/27509.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27509/head:pull/27509

PR: https://git.openjdk.org/jdk/pull/27509