RFR: 8310933: Copying from runtime image to application image should not follow symlinks

[Alexander Matveev]

- Added LinkOption.NOFOLLOW_LINKS when copying pre-define runtime image.
- Added test to cover this change.
- Cleanup RuntimeImageTest.java by removing unused imports and removed incubator from jpackage module name.

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Commit messages:
 - 8310933: Copying from runtime image to application image should not follow symlinks

Changes: https://git.openjdk.org/jdk/pull/16426/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16426&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310933
  Stats: 128 lines in 4 files changed: 114 ins; 9 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/16426.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16426/head:pull/16426

PR: https://git.openjdk.org/jdk/pull/16426