Remove --verified_mem option from the test as there is a plan to deprecate this option.

tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart

Index: tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart
diff --git a/tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart b/tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart
index 783e0793f7f4dc4628736a1d5a7b7989b3b414c9..52a8005216af63bdd195c5adbe1010a11d373920 100644
--- a/tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart
+++ b/tests/lib/convert/streamed_conversion_json_utf8_decode_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Test write barrier verification mode.
-// VMOptions=--verified_mem --verify_before_gc --verify_after_gc --old_gen_growth_rate=1
+// VMOptions=--verify_before_gc --verify_after_gc --old_gen_growth_rate=1
 // VMOptions=
 
 import "package:expect/expect.dart";