Diagnostic improvements to better understand why lib/Benchark.t test 13 has been...

Diagnostic improvements to better understand why lib/Benchark.t test 13 has been failing smoke randomly.

Fix 1: Original code tests for less than but not =. I think that if these values are the same, the test should pass. I don't know the code well enough to be 100% sure. D
Fix 2: convert ok() to cmp_ok() for better diagnostic messages from smoke tests when they happen.
Fix 3: convert print to diag() so it will properly print through harness.