[ELF] Emit Verbose Asm when using --lto-emit-asm

D138560 was abandonned as the use case can already be covered by `-Xoffload-linker --lto-emit-asm`.
However the output from `--lto-emit-asm` doesn't have
comments like the Clang `-S` output.

This patch adds verbose assembly output to LLD ELF LTO
so that the resulting assembly file more closely matches Clang's.

Having comments is especially important on targets such as AMDGPU because
they contain additional information about the kernel(s) being compiled.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D141268