Add testcase for "star_expr".
Add testcase for "star_expr".

wklken/yapf,hayd/yapf,lucius-feng/yapf,bygloam/yapf,google/yapf,thurday/yapf,dmoliveira/yapf,ambv/yapf,elviswf/yapf,jamesblunt/yapf,nikolamilosevic86/yapf,google/yapf,abduld/yapf,sbc100/yapf,sbc100/yapf