RFR: 8350594: Misleading warning about install dir for DMG packaging [v2]

[Alexey Semenyuk]

> - Fix the warning message about the custom installation directory location jpackage issues for DMG runtime packaging.
>  - Don't issue the warning when the `-install-dir` value equals the default installation directory location.

Alexey Semenyuk has updated the pull request incrementally with one additional commit since the last revision:

  Fix bug with not running testDmg() tests

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Changes:
  - all: https://git.openjdk.org/jdk/pull/23752/files
  - new: https://git.openjdk.org/jdk/pull/23752/files/bf4268da..afc341c4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23752&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23752&range=00-01

  Stats: 4 lines in 1 file changed: 1 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/23752.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23752/head:pull/23752

PR: https://git.openjdk.org/jdk/pull/23752