add error info when e2e fails (#1192)
add error info when e2e fails (#1192)


dotnet/docfx,hellosnow/docfx,DuncanmaMSFT/docfx,928PJY/docfx,superyyrrzz/docfx,hellosnow/docfx,928PJY/docfx,DuncanmaMSFT/docfx,superyyrrzz/docfx,LordZoltan/docfx,superyyrrzz/docfx,hellosnow/docfx,LordZoltan/docfx,pascalberger/docfx,LordZoltan/docfx,LordZoltan/docfx,dotnet/docfx,pascalberger/docfx,dotnet/docfx,928PJY/docfx,pascalberger/docfx