[test] make TestRpcHandlerLatencyMetric more robust

This patch addresses a flakiness in the TestRpcHandlerLatencyMetric
that manifests itself on very busy machines or in case of significant
thread scheduling anomalies.

Change-Id: I71685caa1b1a11263bf7843a2a9dab2ba370f3b6
Reviewed-on: http://gerrit.cloudera.org:8080/21055
Tested-by: Alexey Serbin <alexey@apache.org>
Reviewed-by: Mahesh Reddy <mreddy@cloudera.com>
Reviewed-by: Abhishek Chennaka <achennaka@cloudera.com>
1 file changed