[clang] [CLANG][DWARF] Do not emit -ggnu-pubnames for LLDB tuning, unless -ggnu-pubnames is specified. (PR #83331)

[David Blaikie via cfe-commits]

https://github.com/dwblaikie approved this pull request.

Yeah, still not sure why something like `%clang -### -c -target x86_64 -g -gsplit-dwarf %s` wouldn't change behavior on a darwin host and cause the check for gnu-pubnames to fail there.... but if you say that works, guess that's OK & if it doesn't, buildbots will tell us.

https://github.com/llvm/llvm-project/pull/83331