Don't emit anything into the debug_ranges section if we aren't emitting

Don't emit anything into the debug_ranges section if we aren't emitting
any ranges - this includes CU ranges where we were previously emitting an
end list marker even if we didn't have a list.

Testcase includes a test for line table only code emission as the problem
was noticed while writing this test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202357 91177308-0d34-0410-b5e6-96231b3b80d8