Make ios actually fail

Removed Test-iOS from CQ in https://skia-review.googlesource.com/c/skia/+/202130

Bug: skia:8861
Change-Id: I106425525a8149ee955740ae7ecb2eb633a3aa7b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/202127
Reviewed-by: Stephan Altmueller <stephana@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>

dm/DM.cpp

@@ -1636,6 +1636,11 @@ int main(int argc, char** argv) {
             info("\t%s\n", gFailures[i].c_str());
         }
         info("%d failures\n", gFailures.count());
+        // A non-zero return code does not make it to Swarming
+        // An abort does.
+#ifdef SK_BUILD_FOR_IOS
+        SK_ABORT("There were failures!");
+#endif
         return 1;
     }