[llvm-nm] Report '.comment' ELF sections as 'n' instead of '?'

Summary:
The previous implementation reported `.comment` sections as '?'
GNU uses 'n' which means  "The symbol is a debugging symbol."  `.note`  sections are represented as 'n' too.

The test related to this change was updated to CHECK-NEXT to ensure
order and that we did not miss any symbols in the dump.

Reviewers: jhenderson

Reviewed By: jhenderson

Subscribers: rupprecht, llvm-commits

Differential Revision: https://reviews.llvm.org/D57544

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352891 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed