enable MingW on PR
enable MingW on PR

xnagireddy/googletest,jlanecox/googletest,jlanecox/googletest,gianricardo/googletest,jlanecox/googletest,gianricardo/googletest,empiredan/googletest,jlanecox/googletest,google/googletest,antidotcb/googletest,antidotcb/googletest,antidotcb/googletest,antidotcb/googletest,xnagireddy/googletest,google/googletest,gianricardo/googletest,empiredan/googletest,xnagireddy/googletest,empiredan/googletest,xnagireddy/googletest,google/googletest,google/googletest