RFR: 8292316: Tests should not rely on specific JAR file names (jpackage)

[Alexey Semenyuk]

Get rid of dependencies on specific jtreg's jars from jpackage junit tests.

The troublesome statement was `* @library ${jtreg.home}/lib/junit.jar ${jtreg.home}/lib/hamcrest.jar` in "junit.java". The fix removes "junit.java" and the corresponding "run_junit.sh" file and adds jtreg test declarations to each junit test.

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Commit messages:
 - 8292316: Tests should not rely on specific JAR file names (jpackage)

Changes: https://git.openjdk.org/jdk/pull/9944/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9944&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292316
  Stats: 159 lines in 13 files changed: 63 ins; 84 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/9944.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9944/head:pull/9944

PR: https://git.openjdk.org/jdk/pull/9944