Add comments from Eric's review of r204094.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204358 91177308-0d34-0410-b5e6-96231b3b80d8
Remove dead and incorrect code.

is_symlink was always false since it was using stat instead of lstat.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204361 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a couple of typos and an inaccurate description in the new TableGen doc


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204363 91177308-0d34-0410-b5e6-96231b3b80d8