Perform HasFastProperties check on prototypes when computing call targets in Crankshaft.

src/ast.cc

Index: src/ast.cc
diff --git a/src/ast.cc b/src/ast.cc
index 07e50038f69b04507d0f6bb83fdd7afd9252f50e..9d18f6929eee0a47c446aaf26e16827fd10bb5ce 100644
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -528,6 +528,7 @@ bool Call::ComputeTarget(Handle<Map> type, Handle<String> name) {
     if (!type->prototype()->IsJSObject()) return false;
     // Go up the prototype chain, recording where we are currently.
     holder_ = Handle<JSObject>(JSObject::cast(type->prototype()));
+    if (!holder_->HasFastProperties()) return false;
     type = Handle<Map>(holder()->map());
   }
 }