DebugInfo: Make a test more portable

mach-o doesn't like sections without segments, and elf is perfectly
happy with commas in section names, so use a Darwin-like section name.

Suggestion by Eric Christopher.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215052 91177308-0d34-0410-b5e6-96231b3b80d8