[jdk15u-dev] RFR: 8251329: (zipfs) Files.walkFileTree walks infinitely if zip has dir named "." inside

[Yuri Nesterenko]

Clean backport of a rare zipfs issue. A necessary CSR  is in process.

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Commit messages:
 - Backport 3e3051e2ee93142983e9a3edee038e4f7b5ac0f2

Changes: https://git.openjdk.java.net/jdk15u-dev/pull/150/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk15u-dev&pr=150&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8251329
  Stats: 201 lines in 3 files changed: 200 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk15u-dev/pull/150.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk15u-dev pull/150/head:pull/150

PR: https://git.openjdk.java.net/jdk15u-dev/pull/150