Delete jruby kokoro tests.

kokoro/macos/jruby/build.sh

-#!/bin/bash
-#
-# Build file to set up and run tests
-
-# Change to repo root
-cd $(dirname $0)/../../..
-
-# Prepare worker environment to run tests
-source kokoro/macos/prepare_build_macos_rc
-
-./tests.sh jruby

kokoro/macos/jruby/continuous.cfg

-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/macos/jruby/build.sh"
-timeout_mins: 1440

kokoro/macos/jruby/presubmit.cfg

-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/macos/jruby/build.sh"
-timeout_mins: 1440