[SQL] Refined Thrift server test suite

This PR fixes two issues of `HiveThriftServer2Suite` and brings 1 enhancement:

1. Although metastore, warehouse directories and listening port are randomly chosen, all test cases share the same configuration. Due to parallel test execution, one of the two test case is doomed to fail
2. We caught any exceptions thrown from a test case and print diagnosis information, but forgot to re-throw the exception...
3. When the forked server process ends prematurely (e.g., fails to start), the `serverRunning` promise is completed with a failure, preventing the test code to keep waiting until timeout.

So, embarrassingly, this test suite was failing continuously for several days but no one had ever noticed it... Fortunately no bugs in the production were covered under the hood.