Fix crash in SSA builder for receiver-less calls. Not sure this is correct.

dart/frog/leg/lib/js_helper.dart

Index: dart/frog/leg/lib/js_helper.dart
diff --git a/dart/frog/leg/lib/js_helper.dart b/dart/frog/leg/lib/js_helper.dart
index 525d29fbe1216648fa154098b9cc9bf9358da146..6d85849d5770801e6a27b2473bbc5d0c2bd4789a 100644
--- a/dart/frog/leg/lib/js_helper.dart
+++ b/dart/frog/leg/lib/js_helper.dart
@@ -552,12 +552,11 @@ builtin$addAll$1(receiver, collection) {
   }
 }
 
-// TODO(ahe): Investigate why this method causes a compiler crash.
-XXX_builtin$addLast$1(receiver, value) {
+builtin$addLast$1(receiver, value) {
   checkNull(receiver);
   if (!isJSArray(receiver)) return UNINTERCEPTED(receiver.addLast(value));
 
-  throw @'builtin$addLast$1 is not implemented';
+  JS("Object", @"$0.push($1)", receiver, value);
 }
 
 builtin$clear$0(receiver) {
@@ -566,12 +565,14 @@ builtin$clear$0(receiver) {
   receiver.length = 0;
 }
 
-// TODO(ahe): Investigate why this method causes a compiler crash.
-XXX_builtin$forEach$1(receiver, f) {
+builtin$forEach$1(receiver, f) {
   checkNull(receiver);
   if (!isJSArray(receiver)) return UNINTERCEPTED(receiver.forEach(f));
 
-  throw @'builtin$forEach$1 is not implemented';
+  var length = JS("num", @"$0.length", receiver);
+  for (var i = 0; i < length; i++) {
+    f(JS("Object", @"$0[$1]", receiver, i));
+  }
 }
 
 builtin$getRange$2(receiver, start, length) {