validate: Add an infrastructure to be able to implement benchmarking tests
Submitted by Thibault Saunier @thiblahute
Link to original bug (#737276)
Description
Currently GstValidate is not really usefull to implement benchmarking tests, we should make sure that we can easily benchmark pipeline/element one by one, about different variable.
I must also allow us verify that over runs there is no critical performance regressions.