RFR: 8298619: java/io/File/GetXSpace.java is failing [v2]

[Brian Burkhalter]

> Modify the `Space` instances used for size comparison to be created with total number of bytes derived from the Windows `diskFree` utility instead of Cygwin’s `df`.

Brian Burkhalter has updated the pull request incrementally with two additional commits since the last revision:

 - 8298619: Load GetDiskSpaceInformationW dynamically
 - 8298619: Replace df and diskFree with native calls

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12397/files
  - new: https://git.openjdk.org/jdk/pull/12397/files/9eef8cd9..42ad4cea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12397&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12397&range=00-01

  Stats: 340 lines in 3 files changed: 206 ins; 97 del; 37 mod
  Patch: https://git.openjdk.org/jdk/pull/12397.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12397/head:pull/12397

PR: https://git.openjdk.org/jdk/pull/12397