A pattern to convert `spv.CompositeInsert` and `spv.CompositeExtract`.
In LLVM, there are 2 ops that correspond to each instruction depending
on the container type. If the container type is a vector type, then
the result of conversion is `llvm.insertelement` or `llvm.extractelement`.
If the container type is an aggregate type (i.e. struct, array), the
result of conversion is `llvm.insertvalue` or `llvm.extractvalue`.
Reviewed By: mravishankar
Differential Revision: https://reviews.llvm.org/D88205
b81bedf714