Fix to handle loop variables not declared in the for.

pkg/analyzer/test/services/data/stmt_tests.data

 >>>
 if (x &&
     y) {
   print('!');
 }
 <<<
 if (x && y) {
   print('!');
 }
 >>>
 for (var a=0; a<100; ++a) { print(a); }
 <<<
 for (var a = 0; a < 100; ++a) {
   print(a);
 }
 >>>
 for(
 var a=0;
 a<100; 
 ++a)
 { 
 print(a);
 }
 <<<
 for (var a = 0; a < 100; ++a) {
   print(a);
+}
+>>>
+for (x in xs) {
+  print(x);
+}
+<<<
+for (x in xs) {
+  print(x);
 }