cmake: When adding lit testsuites, ignore Output directories

With in-tree builds we can get Output directories scattered among our
tests. Recursing into those to find tests doesn't make sense.

Thanks to nlewycky for noticing this!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276667 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed