Update date_time.

tool/sdk_expected_errors.txt

Index: tool/sdk_expected_errors.txt
diff --git a/tool/sdk_expected_errors.txt b/tool/sdk_expected_errors.txt
index db066687effa020573653097a7d320e4761d3897..7af8fc8af6f7a4c68fba178910ac0a67ca978d81 100644
--- a/tool/sdk_expected_errors.txt
+++ b/tool/sdk_expected_errors.txt
@@ -3,7 +3,7 @@
 [error] Invalid override. The type of NativeTypedArrayOfDouble.[]= ((int, num) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:_native_typed_data, line 793, col 3)
 [error] Invalid override. The type of _JsonStringStringifierPretty.writeIndentation ((int) → void) is not a subtype of _JsonPrettyPrintMixin.writeIndentation ((dynamic) → void). (dart:convert/json.dart, line 875, col 3)
 [error] Invalid override. The type of _JsonUtf8StringifierPretty.writeIndentation ((int) → void) is not a subtype of _JsonPrettyPrintMixin.writeIndentation ((dynamic) → void). (dart:convert/json.dart, line 1034, col 3)
-[error] Invalid override. The type of DateTime.compareTo ((DateTime) → int) is not a subtype of Comparable<dynamic>.compareTo ((dynamic) → int). (dart:core/date_time.dart, line 412, col 3)
+[error] Invalid override. The type of DateTime.compareTo ((DateTime) → int) is not a subtype of Comparable<dynamic>.compareTo ((dynamic) → int). (dart:core/date_time.dart, line 448, col 3)
 [error] Annotation can be only constant variable or constant constructor invocation (dart:core/stacktrace.dart, line 27, col 3)
 [error] Invalid override. The type of FileList.[]= ((int, File) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 16869, col 3)
 [error] Invalid override. The type of HtmlCollection.[]= ((int, Node) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 18904, col 3)