[test] Require 'asserts' for a test which uses -debug-only

Without this line, bots which run check-all on Release compilers will
break.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266386 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed