Fix missing comma for empty arrays/sets When an array or a set is empty, and if it's not the last property within an object, we need to add a comma after empty brackets/braces. This change fix this issue. Also updated a test case to capture this. Signed-off-by: Kasun Athukorala <kasunath@google.com> Change-Id: Ia087f341d052660191f2614add2060c81be67f61