Remove _StdSink._isTranslatable field.

pkg/dev_compiler/tool/sdk_expected_errors.txt

Index: pkg/dev_compiler/tool/sdk_expected_errors.txt
diff --git a/pkg/dev_compiler/tool/sdk_expected_errors.txt b/pkg/dev_compiler/tool/sdk_expected_errors.txt
index 73e951265e7ac366293858e28360418989b33e7f..7fe9f59819f490903640a5e258e808d93df5c2fc 100644
--- a/pkg/dev_compiler/tool/sdk_expected_errors.txt
+++ b/pkg/dev_compiler/tool/sdk_expected_errors.txt
@@ -100,7 +100,6 @@ Consider passing explicit type argument(s) to the generic.
 [warning] The final variables 'form', 'labels' and '5' more must be initialized. (dart:html, line 33132, col 3)
 [warning] The final variables 'readyState' and 'track' must be initialized. (dart:html, line 34173, col 3)
 [warning] The final variables 'decodedFrameCount', 'droppedFrameCount' and '2' more must be initialized. (dart:html, line 34889, col 3)
-[warning] The final variable '_isTranslatable' must be initialized. (dart:io/stdio.dart, line 327, col 3)
 [warning] The final variables 'href' and 'target' must be initialized. (dart:svg, line 56, col 3)
 [warning] The final variables 'requiredExtensions', 'requiredFeatures' and '2' more must be initialized. (dart:svg, line 512, col 3)
 [warning] The final variables 'cx', 'cy' and '1' more must be initialized. (dart:svg, line 587, col 3)