[dsymutil] Skip mach-o paired relocations

Noticed while working on scattered relocations.
I do not think these relocs can actually happen in the debug_info section,
but if they happen the code would mishandle them. Explicitely skip them
and warn if we encounter one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259341 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed