[RFC] TensorIR: A schedulable IR for TVM

How is the compilation speed compared to the original TE? In Ansor/Autotvm, we have to compile a lot of schedules for feature extraction, so the speed of schedule transformation matters.

Do you have any benchmark results? Intuitively, I think the original TE will be faster because it can do a batched bound inference and AST construction. If it is true, how can we fix this performance gap?