Cleanup AcceptorTest logic
Cleanup AcceptorTest logic

Summary: There is no need to pass the boolean of which test mode we are running in into getTestSslContextConfig when we can just access the test config instead

Reviewed By: samuelrm

Differential Revision: D31744791

fbshipit-source-id: ea883831f1679270dc438d8a68eb61285d38c282

facebook/wangle,facebook/wangle,facebook/wangle