[debug] dump build output

context: https://bugzilla.xamarin.com/show_bug.cgi?id=57828

this commit should be reverted.

Author: lewurm

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest.cs

@@ -1527,6 +1527,7 @@ public interface OnFooListener
 			using (var builder = CreateDllBuilder (path, false, false)) {
 				try {
 					builder.Build (proj);
+					Console.WriteLine ("build output:\n<<<<start>>>>\n" + builder.LastBuildOutput + "\n<<<<end>>>>");
 					if (failureExpected)
 						Assert.Fail ("Build should fail.");
 					if (expectedWarning == null)