[ELF] - Added testcase gdb-index-ranges.s (https://reviews.llvm.org/D32750)

[ELF] - Added testcase gdb-index-ranges.s (https://reviews.llvm.org/D32750)

Before rL301170 was landed, LLD did not produce correct entries in .gdb_index address area.
Issue was fixed on LLVM DWARF parsers side and was relative to how .debug_ranges
section was scanned. It was main problem of PR32319.

It makes sense to have testcase on LLD size too. This checks that we generate proper values
now, because we do not have any tests for .gdb_index which works with .debug_ranges atm.

Differential revision: https://reviews.llvm.org/D32750

llvm-svn: 302006