DI: Update testcases for LLVM assembly change

Update testcases after LLVM change r243774.

Most of these had no need to check `tag:` field, but did so as a way of
getting to the `name:` field.  In a few cases I've converted the `tag:`
checks to `arg:` or `CHECK-NOT: arg:`.

llvm-svn: 243775
20 files changed