[crankshaft] Add baseline implementation of for-of.

src/typing.cc

Index: src/typing.cc
diff --git a/src/typing.cc b/src/typing.cc
index fb758828b076524a47c6be702050437507d4be95..07e8416e7d232cae12c74332f0d969d0f13f02f0 100644
--- a/src/typing.cc
+++ b/src/typing.cc
@@ -299,7 +299,14 @@ void AstTyper::VisitForInStatement(ForInStatement* stmt) {
 
 void AstTyper::VisitForOfStatement(ForOfStatement* stmt) {
   RECURSE(Visit(stmt->iterable()));
+  RECURSE(Visit(stmt->assign_iterator()));
   store_.Forget();  // Control may transfer here via looping or 'continue'.
+  RECURSE(Visit(stmt->next_result()));
+  // Collect type feedback.
+  stmt->result_done()->RecordToBooleanTypeFeedback(oracle());
+  ObserveTypesAtOsrEntry(stmt);
+  RECURSE(Visit(stmt->result_done()));
+  RECURSE(Visit(stmt->assign_each()));
   RECURSE(Visit(stmt->body()));
   store_.Forget();  // Control may transfer here via 'break'.
 }