cluster-pod-kernel-args: generates too-small Offsets, but correct output in descriptormap

[dneto0]

Example:

kernel void align(global int* A, int x, float4 c) {
  *A = x + (int)c.x;
}

Compile with:
clspv align.cl -o align.spv -cluster-pod-kernel-args -descriptormap=foot

Then the x and c arguments are collected into a single struct argument, for a storage buffer. The descriptor map is:

kernel,align,arg,A,argOrdinal,0,descriptorSet,0,binding,0,offset,0
kernel,align,arg,x,argOrdinal,1,descriptorSet,0,binding,1,offset,0
kernel,align,arg,c,argOrdinal,2,descriptorSet,0,binding,1,offset,16

That's correct.

However, in SPIR-V we have:
OpMemberDecorate %_struct_8 0 Offset 0
OpMemberDecorate %_struct_8 1 Offset 4 ; this should be offset 16

So two bugs, really: Mismatch between descriptormap and the declared struct offset. Should make the declared struct offset the same as what's reported in the descriptormap.