Add a test for common symbols in coff.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200803 91177308-0d34-0410-b5e6-96231b3b80d8
Fix wording of warning message about invalid debug info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200806 91177308-0d34-0410-b5e6-96231b3b80d8
Update testing case for r200806.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200807 91177308-0d34-0410-b5e6-96231b3b80d8
Small fix for llvm-nm handling of weak symbols on ELF (print 'v').

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200808 91177308-0d34-0410-b5e6-96231b3b80d8