[jdk8u-dev] RFR: 8309841: Jarsigner should print a warning if an entry is removed

[Roman Marchenko]

This is backport of "8309841: Jarsigner should print a warning if an entry is removed"

Original patch does not apply cleanly to jdk8:
- some minor conflicts in JDK code
- files moved to appropriate locations
-  added the check in `jdk/src/share/classes/sun/security/tools/jarsigner/Main.java` at line 1196
- `ed25519` algorithm was replaced with `RSA` in `RemovedFiles.java`
- `JarEntry copyEntry()` procedure was manually added to `JarUtils.java` to make `JarUtilsTest` working.
- the tests were adapted to Java 8, including replaced `Path.of`, `Files.writeString`, package names, and arrays processing as well.

We need this fix in jdk8, as all versions have this issue with jarsigner.

New tests successfully ran locally on Linux, x86_64.

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Commit messages:
 - Backport bdfb41f977258831e4b0ceaef5d016d095ab6e7f

Changes: https://git.openjdk.org/jdk8u-dev/pull/635/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=635&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309841
  Stats: 259 lines in 5 files changed: 258 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/635.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/635/head:pull/635

PR: https://git.openjdk.org/jdk8u-dev/pull/635