<i18n dev> RFR: 8290316: Ensure that all directory streams are closed in java.base

[Ryan Ernst]

This commit guards uses of Files methods returning path streams in
java.base to use try-with-resources.

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Commit messages:
 - 8290316: Ensure that all directory streams are closed in java.base

Changes: https://git.openjdk.org/jdk/pull/9518/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9518&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290316
  Stats: 52 lines in 5 files changed: 12 ins; 7 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/9518.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9518/head:pull/9518

PR: https://git.openjdk.org/jdk/pull/9518