Use preinstalled JDK in AppVeyor build
Try to switch to jdk 1.8 for windows CI build
Revert "Try to switch to jdk 1.8 for windows CI build"

This reverts commit b0481870b15210c86d3a6036f22e225258ccba55.
Merge branch 'groovy-1.8' into groovy-1.9
Merge branch 'groovy-1.9' into groovy-2.3