RFR: 8316547: Use JUnit.dir jtreg property with jpackage JUnit tests

[Alexey Semenyuk]

Strip

/*
 * @test
 * @modules jdk.jpackage
 * @compile --patch-module jdk.jpackage=${test.src} --add-reads jdk.jpackage=ALL-UNNAMED --add-exports jdk.jpackage/jdk.jpackage.internal=ALL-UNNAMED AppImageFileTest.java
 * @run junit/othervm --patch-module jdk.jpackage=${test.classes} --add-reads jdk.jpackage=ALL-UNNAMED --add-exports jdk.jpackage/jdk.jpackage.internal=ALL-UNNAMED jdk.jpackage.internal.AppImageFileTest
 */

comment from jpackage JUnit tests and instruct jtreg to run them through `JUnit.dirs` property.

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Commit messages:
 - 8316547: Use JUnit.dir jtreg property with jpackage JUnit tests

Changes: https://git.openjdk.org/jdk/pull/15826/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15826&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316547
  Stats: 1407 lines in 19 files changed: 669 ins; 735 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15826.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15826/head:pull/15826

PR: https://git.openjdk.org/jdk/pull/15826