[GlobalIsel] Assertion when generating code for ptrtoint with vector operands

[arichardson]

The following IR when run with llc -mtriple=x86_64-linux-gnu -global-isel -verify-machineinstrs

define <2 x i64> @ptrtoint_vec(<2 x ptr> %p) {
entry:
  %addr = ptrtoint <2 x ptr> %p to <2 x i64>
  %ret = xor <2 x i64> %addr, <i64 -1, i64 -1>
  ret <2 x i64> %ret
}

triggers the following assertion:

llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp:1428: virtual MachineInstrBuilder llvm::MachineIRBuilder::buildInstr(unsigned int, ArrayRef, ArrayRef, std::optional): Assertion `(TypeSize::ScalarTy)SrcOps.size() * SrcOps[0].getLLTTy(*getMRI()).getSizeInBits() == DstOps[0].getLLTTy(*getMRI()).getSizeInBits() && "input scalars do not exactly cover the output vector register"' failed.