Add a new file to test the code gen for common linkage symbol. Remove common linkage in some other testcases to avoid distraction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372426 91177308-0d34-0410-b5e6-96231b3b80d8
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369877 91177308-0d34-0410-b5e6-96231b3b80d8