[ComplexDeinterleave] Don't try to combine single FP reductions. (#139469)
Currently the apss tries to combine floating point reductions, without
checking for the correct fast-math flags and it also creates invalid IR
(using llvm.reduce.add for FP types).
For now, just bail out for non-integer types.
PR: https://github.com/llvm/llvm-project/pull/139469