[CIR] Fix lowering after 2929a2978cc3bdb0ff12a0e5d0a9236ff221f668
- After 2929a2978cc3bdb0ff12a0e5d0a9236ff221f668,
`ConversionPatternRewriter::replaceAllUsesWith` behavior is changed
from the previous immediate mode into a delayed fashion. The legacy
operation of `replaceAllUsesWith` followed by `eraseOp` is no longer
working, replace that sequence with `replaceOp`.