Add additional test-case for one-line-function.

This ensures that we format:
void longFunctionName {
} // long comment here

And not:
void longFunctionName {}
// long comment here

As requested in post-commit-review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182024 91177308-0d34-0410-b5e6-96231b3b80d8