Instrument and extend monitoring / timing diagnostics for periodic & delete perf test cases of splinter_test. #356

Issue #354, timing / diagnostics monitoring will be added to --perf and --parallel-perf test cases of splinter_test.
Apply similar enhanced monitoring & diagnostics / tracing to test_splinter_periodic() and test_splinter_delete() test cases.

We [will] need this to monitor (expected to-be-slow) performance characteristics of these cases for larger workloads.

This instrumentation is necessary to stabilize these test runs for inclusion to nightly test runs.