[X86] Remove (V)MOVHPDrm patterns that involve bitcast+scalar_to_vec+loadi64.

I think these are left over from when we used to type legalize
v2f32 loads using bitcast+scalar_to_vec+loadi64 on 64-bit targets.
These days we use loadf64. If this becomes a problem a better
solution would be a DAG combine to turn it into scalar_to_vec+loadf64.