CSHARP-3707: Force EG variant running all tests projects even some of them were failed. (#549)

Author: DmitryLukyanov

build.cake

@@ -160,7 +160,8 @@ Task("Test")
             testProject.FullPath,
             settings
         );
-    });
+    })
+    .DeferOnError();
 
 Task("TestNet452").IsDependentOn("Test");
 Task("TestNetStandard15").IsDependentOn("Test");