[jdk11u-dev] RFR: 8208077: File.listRoots performance degradation

[Victor Rudometov]

Backport of https://bugs.openjdk.org/browse/JDK-8208077
Clean backport for parity with 11.0.19-oracle.
Simple change, low risk. Windows only. 

Checked on Linux x64 and Windows x64 pipelines.

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Commit messages:
 - 8208077: File.listRoots performance degradation

Changes: https://git.openjdk.org/jdk11u-dev/pull/1681/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1681&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8208077
  Stats: 29 lines in 2 files changed: 17 ins; 1 del; 11 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1681.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1681/head:pull/1681

PR: https://git.openjdk.org/jdk11u-dev/pull/1681