More extensive error handling for 'unresolved' cases.

test/kernel/regression/unresolved_for_in.dart.txt

 library;
 import self as self;
 import "dart:core" as core;
 
 class Fisk extends core::Object {
   constructor •() → self::Fisk
     : super core::Object::•();
   method it1(dynamic x) → dynamic {
     for(final dynamic #t1 in x) {
       this.key = #t1;
@@ skipping 14 matching lines @@
     for(final dynamic #t8 in x) {
       let final dynamic #t9 = #t8 in invalid-expression;
       core::print(this.key);
     }
   }
 }
 static method main(dynamic arguments) → dynamic {
   new self::Fisk::•();
   for(final dynamic #t10 in arguments) {
     let final dynamic #t11 = #t10 in invalid-expression;
-    core::print(invalid-expression);
+    core::print(throw core::_genericNoSuchMethod(null, #key, <dynamic>[], <dynamic, dynamic>{}, null));
   }
   for(final dynamic #t12 in arguments) {
     let final dynamic #t13 = #t12 in invalid-expression;
     core::print(self::Fisk);
   }
   for(final dynamic #t14 in arguments) {
     let final dynamic #t15 = #t14 in invalid-expression;
     core::print(invalid-expression);
   }
   for(final dynamic #t16 in arguments) {
     let final dynamic #t17 = #t16 in invalid-expression;
     core::print(() → void);
   }
   for(final dynamic #t18 in arguments) {
     let final dynamic #t19 = #t18 in invalid-expression;
-    core::print(invalid-expression);
+    core::print(throw core::_genericNoSuchMethod(null, #key, <dynamic>[], <dynamic, dynamic>{}, null));
   }
 }