COFF: move ARM COFF test to ARM directory

The COFF tests all assume X86.  Just move the new COFF tests under ARM to
appease the build bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207346 91177308-0d34-0410-b5e6-96231b3b80d8
tests: Windows ARM now supports object emission

Update lit.cfg with the fact that LLVM can now generate WoA PE/COFF objects.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207347 91177308-0d34-0410-b5e6-96231b3b80d8