[SanbdoxVec][BottomUpVec] Fix diamond shuffle with multiple vector inputs (#126965)
When the operand comes from multiple inputs then we need additional
packing code. When the operands are scalar then we can use a single
InsertElementInst. But when the operands are vectors then we need a
chain of ExtractElementInst and InsertElementInst instructions to insert
the vector value into the destination vector. This is what this patch
implements.