fix stringutil tests
fix stringutil tests

Change-Id: Ie6ad5645ac6fca6af22376f2fda00e1c4772ae19

gunwoo-nixgon/outyet,nativetouch/example,nativetouch/example,golang/example,gunwoo-nixgon/outyet,wdproductions/simplego,Jimmy-Xu/example,WillahScott/example,WillahScott/example,wallclockbuilder/example,WillahScott/example,Jimmy-Xu/example,gunwoo-nixgon/outyet,golang/example,golang/example,wdproductions/simplego,nativetouch/example,wdproductions/simplego,wallclockbuilder/example,Jimmy-Xu/example,wallclockbuilder/example