RFR: 1604: Unify behavior in gradlew and gradlew.bat [v2]

[Erik Joelsson]

> This patch changes the gradlew.bat script to download and extract Gradle and the JDK in the same locations as the gradlew bash script, so that running either script interchangeably works fine in the same workspace.

Erik Joelsson has updated the pull request incrementally with one additional commit since the last revision:

  Restoring mkdir

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Changes:
  - all: https://git.openjdk.org/skara/pull/1377/files
  - new: https://git.openjdk.org/skara/pull/1377/files/50284f28..33d7eb66

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1377&range=01
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1377&range=00-01

  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/skara/pull/1377.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1377/head:pull/1377

PR: https://git.openjdk.org/skara/pull/1377