Auto merge of #133899 - scottmcm:strip-mir-debuginfo, r=oli-obk

We don't need `NonNull::as_ptr` debuginfo

In order to stop pessimizing the use of local variables in core, skip debug info for MIR temporaries in tiny (single-BB) functions.

For functions as simple as this -- `Pin::new`, etc -- nobody every actually wants debuginfo for them in the first place.  They're more like intrinsics than real functions, and stepping over them is good.