[InterleavedAccessPass] Get round the unsupported large scalarize vectors (#88643)

When build with option -msve-vector-bits=512, the return vaule of
Subtarget->getMinSVEVectorSizeInBits() is 512;
While the MinElts is still 4 for <vscale x 4 x double> in
getNumInterleavedAccesses, so it creates invalid
llvm.aarch64.sve.ld2.sret.nxv4f64, which need be splited.
Unlikely, the related custom spilting is not supported now.

Fix https://github.com/llvm/llvm-project/issues/88247