Add performance tests in sanity check mode to buildbot (Feature #1770)

Most of our performance test have a simple sanity checks to validate the correctness of output.
I suggest adding them to buildbot to control the regression.

To run the performance tests in sanity check mode you need to do:

1. Set OPENCV_TEST_DATA_PATH as for regular tests
2. add --perf_min_samples=1 --perf_force_samples=1 to the test arguments.
   For example:

opencv_perf_core --perf_min_samples=1 --perf_force_samples=1

For now these checks are working for the following modules:

• core
• imgproc
• calib3d
• photo

But it makes sense to add perf tests for the other modules as well. Currently running all performance tests in sanity mode takes less than 1 minute on my desktop.

Standard output of perf tests is very close to the output of our accuracy tests so it should not be difficult to integrate.