[dart2js] Remove unused JS interop check enum.

Change-Id: If8b3fce59277aac42cdb453a1f270d5600581a5e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/168990
Reviewed-by: Srujan Gaddam <srujzs@google.com>
Commit-Queue: Riley Porter <rileyporter@google.com>
diff --git a/pkg/compiler/lib/src/diagnostics/messages.dart b/pkg/compiler/lib/src/diagnostics/messages.dart
index 0271281..2efebfa 100644
--- a/pkg/compiler/lib/src/diagnostics/messages.dart
+++ b/pkg/compiler/lib/src/diagnostics/messages.dart
@@ -76,7 +76,6 @@
   JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS,
   JS_INTEROP_FIELD_NOT_SUPPORTED,
   JS_INTEROP_NON_EXTERNAL_MEMBER,
-  JS_INTEROP_METHOD_WITH_NAMED_ARGUMENTS,
   JS_OBJECT_LITERAL_CONSTRUCTOR_WITH_POSITIONAL_ARGUMENTS,
   JS_PLACEHOLDER_CAPTURE,
   LIBRARY_NOT_FOUND,