[CalcSpillWeights] don't mark live intervals with spillable inlineasm ops as...

[CalcSpillWeights] don't mark live intervals with spillable inlineasm ops as having infinite spill weight (#70747)

This is necessary for RegAllocGreedy support for memory folding inline
asm that uses "rm" constraints.

Thanks to @qcolombet for the suggestion.

Link: https://github.com/llvm/llvm-project/issues/20571