[jdk15u-dev] RFR: 8286594: (zipfs) Mention paths with dot elements in ZipException and cleanups

[Yuri Nesterenko]

Backporting this fix as an important follow-up to JDK-8251329. Clean backport. Tier1, zipfs -specific tests pass.

-------------

Commit messages:
 - Backport 80cf9f3464c599fb7860432bf4ed506a3b298d8e

Changes: https://git.openjdk.org/jdk15u-dev/pull/258/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk15u-dev&pr=258&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286594
  Stats: 73 lines in 1 file changed: 31 ins; 38 del; 4 mod
  Patch: https://git.openjdk.org/jdk15u-dev/pull/258.diff
  Fetch: git fetch https://git.openjdk.org/jdk15u-dev pull/258/head:pull/258

PR: https://git.openjdk.org/jdk15u-dev/pull/258