clang-format: Fix column layout with a comment in the last line.

Before:
  int aaaaa[] = {
      1, 2,
      3, // comment
      4, 5,
      6  // comment
  };

After:
  int aaaaa[] = {
      1, 2, 3, // comment
      4, 5, 6  // comment
  };

llvm-svn: 242299