Testing framework should check for performance regression

[rcabell]

The testing framework should compare runtime for each test from candidate to reference and flag significant* differences as a regression.

*"significant" is in the eye of the beholder

Expected Behavior

If a candidate test runs more than xx% slower than the reference test, it should be labeled as a regression

Current Behavior

No differences in test runtimes are noted or flagged

Possible Solution

For each candidate test run by the testing framework, a runtime should be noted and compared against the runtime.