[bindings/go] Add Go bindings to LLVMGetIndices
Summary: This instruction is useful for inspecting extractvalue/insertvalue in IR. Unlike most other operations, indices cannot be inspected using the generic Value.Opcode() function so a specialized function needs to be added.
Reviewers: whitequark, pcc
Reviewed By: whitequark
Differential Revision: https://reviews.llvm.org/D53883