[Hybrid Script] Supporting scheduling hybrid script (#2416)

* on the way to enable hybrid schedule

* I think I am done with imperfect loop split?

* copyright watermark

* loop annotation

* fix lint

* fix lint 1

* shit!

* loop reorder supported

* support bind to add some tests

* fused tested

* imperfect loop testcase

* fix lint

* add bind testcase

* fix doc

* fix online edit typo

* resolve @mercymercy review

* fix indent

* i should convince myself it is not flaky test first

* fix test hybrid

* how many flaky test are you expecting; i ball ball u to let me pass

* rebase halide...