RFR: 8321616: Convert the ReadZip test to JUnit

[Eirik Bjorsnos]

Please review this PR which suggests we rewrite the `../zip/ZipFile/ReadZip.java` test to JUnit. 

The current test is a single main method with a sequence of fairly unrelated scenarios. It would benefit from a rewrite to multiple JUnit test methods and some general modernization and simplification of the code.

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Commit messages:
 - Update copyright year
 - Convert ReadZip to JUnit

Changes: https://git.openjdk.org/jdk/pull/17038/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17038&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8321616
  Stats: 222 lines in 1 file changed: 80 ins; 48 del; 94 mod
  Patch: https://git.openjdk.org/jdk/pull/17038.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17038/head:pull/17038

PR: https://git.openjdk.org/jdk/pull/17038