All code must use the context from Ginkgo when doing API calls or polling for a
change, otherwise the code would not return immediately when the test gets
aborted.
PokeUDP() is used at e2e service subpackage only, so this moves the
function and the related code to the subpackage for making e2e core
framework small.
When test/e2e/framework/service was first created, a lot of service
test code got crammed into TestJig even though it didn't use any of
TestJig's members. Make that code available outside of TestJig.
