tweak test case for debugging bot

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217906 91177308-0d34-0410-b5e6-96231b3b80d8
This add a reset method for WinCOFFObjectWriter, like other MC* classes.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217907 91177308-0d34-0410-b5e6-96231b3b80d8