RFR: 8339154: Cleanups and JUnit conversion of test/jdk/java/util/zip/Available.java

[Eirik Bjørsnøs]

Please review this test-only PR which addresses several issues with the `test/jdk/java/util/zip/Available.java` test:

* The test is converted to JUnit 5
* The test now creates its own test vector programmatically instead of relying on a binary `input.jar` test vector 
*  Coverage is added for calling `available()` after calling `ZipInputStream.closeEntry`, as expected by the API specification for `ZipInputStream.available`
* Coverage is added for calling `available()` on a closed `ZipInputStream`
* Coverage is added for the unspecified, but long-standing behavior of `ZipFileInputStream.available()` (The InputStream returned for `STORED` entries)

Additionally, the test is split into multiple methods, adding javadoc comments for each of them.

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Commit messages:
 - Add coverage for calling available() on a closed ZipInputStream
 - Clean up the Available test and convert it to JUnit 5

Changes: https://git.openjdk.org/jdk/pull/20744/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20744&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339154
  Stats: 145 lines in 1 file changed: 103 ins; 10 del; 32 mod
  Patch: https://git.openjdk.org/jdk/pull/20744.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20744/head:pull/20744

PR: https://git.openjdk.org/jdk/pull/20744