Update stmt_list value to point to new .debug_line offset.

Summary:
After we add new line number information we have to update stmt_list
offsets in .debug_info. For this I had to add a primitive relocations
support for non-allocatable sections we are copying from input file.

Also enabled functionality to process relocations in non-allocatable
sections that LLVM is generating, such as .debug_line. I thought
we already had it, but apparently it didn't work, at least not
for ELF binaries.

(cherry picked from FBD3037903)