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.
This makes sub packages of e2e test framework to use log functions
of core framework instead for avoiding circular dependencies.
NOTE: test/e2e/framework/ssh will make circular dependencies if
updating it. It is necessary to solve the issue in advance
before this work.
