* Enable TTY password OS tests, plus refactoring (#57759)
Two keystore tests were unintentionally ignored when the
password-protected keystore work was merged. I've reënabled those tests
here.
I've also refactored the test methods a little bit to reduce the API
surface: instead of having a "startElasticsearchTtyPassword" method and
a "startElasticsearchStandardInputPassword" method, I've made a single
"startElasticsearch" method with a "useTty" boolean argument.
* Separate daemonization and non-daemonization case for tty
Centos 6 uses a version of expect that kills the elasticsearch process
when it tries to daemonize. I will fix this in future work but for now
I'm replacing it with a todo.
958b21d727