[SPARK-2929][SQL] Refactored Thrift server and CLI suites

Removed most hard coded timeout, timing assumptions and all `Thread.sleep`. Simplified IPC and synchronization with `scala.sys.process` and future/promise so that the test suites can run more robustly and faster.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #1856 from liancheng/thriftserver-tests and squashes the following commits:

2d914ca [Cheng Lian] Minor refactoring
0e12e71 [Cheng Lian] Cleaned up test output
0ee921d [Cheng Lian] Refactored Thrift server and CLI suites

(cherry picked from commit cae9414d3805c6cf00eab6a6144d8f90cd0212f8)
Signed-off-by: Michael Armbrust <michael@databricks.com>