[dsymutil] Support scattered relocs.

Although it seems like clang will never emit scattered relocations in
the debug information (at least I couldn't find a way), we have too
support them for the benefit of other compilers.
As clang doesn't generate them, the included testcase was produced
from hacked up assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259339 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed