swift

a1338076 - Add type checker performance tests.

Add type checker performance tests. Add type checker performance tests under validation-test/Sema/type_checker_perf. Under ./fast/ we have tests that compile reasonably quickly now but at one point did not. Under ./slow/ we have tests that are still very slow to compile. Some tests use %scale-test and others -solver-expression-time-threshold to determine if they are scaling well or compiling fast enough. I've got several more tests gathered that have not yet been set up to run in our test system. Those are forthcoming! Further contributions welcome. Thanks go to @xedin who helped collect most of the test cases.