[Integrated] RFR: Update to Gradle 5.6.2

[duke]

Changeset: 91f05bc4
Author:    Erik Helin <ehelin at openjdk.org>
Date:      2019-09-18 08:02:50 +0000
URL:       https://git.openjdk.java.net/skara/commit/91f05bc4

Update to Gradle 5.6.2

Reviewed-by: rwestberg

! deps.env
! test.dockerfile