Support JMH benchmarks from Jenkins Test Harness (#4135)

* Support running JMH benchmarks from JTH 2.51

* Fix NPE caused by ExtensionFinderTest
* A test for running a sample benchmark
* Bump up JTH to 2.54
* git ignore the report produced by benchmarks

* Fix BindException in BootFailureTest

* Fix NPE during `tearDown()` in CustomPluginManagerTest

JenkinsRule >= 2.50 does not ignore errors during Jenkins shutdown