Rollup merge of #146552 - cjgillot:resume-noremap, r=jackh726

StateTransform: Do not renumber resume local.

MIR parameters are not explicitly assigned-to when entering the MIR body. If we want to save their values inside the coroutine state, we need to do so explicitly.

This was done by renaming the `_2` local, and introducing an explicit assignment pre-transform. This particular trick confuses me.

This version makes explicit that we are assigning parameters to saved locals.

r? ``@dingxiangfei2009``

Author: Zalathar