generate_gradle.py: Fix junit_binary(), enable --all by default

Also updates templates for gradle plugin 3.0 and makes
--split-project work again for Chromium codebase.

Bug: 620034, webrtc:8547, 786676
Change-Id: I89e937ff8a70cf30f890765b98efa0d331fba77e
Reviewed-on: https://chromium-review.googlesource.com/779499
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518312}
5 files changed