GEODE-9251 (#6471)
GEODE-9251 (#6471)

capture gradle exit code for exit. Subshell taskkill in case of error.
make the windows optional command only impact windows builds
jdeppe-pivotal/geode,masaki-yamakawa/geode,smgoller/geode,masaki-yamakawa/geode,smgoller/geode,smgoller/geode,smgoller/geode,jdeppe-pivotal/geode,masaki-yamakawa/geode,jdeppe-pivotal/geode,jdeppe-pivotal/geode,masaki-yamakawa/geode,masaki-yamakawa/geode,jdeppe-pivotal/geode,masaki-yamakawa/geode,smgoller/geode,jdeppe-pivotal/geode,smgoller/geode,masaki-yamakawa/geode,smgoller/geode,jdeppe-pivotal/geode