clang-format: Fix corner case working around one-per-line dict literals.

Before:
  var object_literal_with_long_name = {
    a: 'aaaaaaaaaaaaaaaaaa', b: 'bbbbbbbbbbbbbbbbbb'
  };

After:
  var object_literal_with_long_name = {
    a: 'aaaaaaaaaaaaaaaaaa',
    b: 'bbbbbbbbbbbbbbbbbb'
  };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209296 91177308-0d34-0410-b5e6-96231b3b80d8