[turbofan] Flatten cons strings before embedding them into optimized code.

src/compiler/js-context-specialization.cc

Index: src/compiler/js-context-specialization.cc
diff --git a/src/compiler/js-context-specialization.cc b/src/compiler/js-context-specialization.cc
index 8bbfe1e9498ddf1750408b620e2ebfbe55b17c60..4d9d1d950412321d03cefc884a1f3e6d47476f9d 100644
--- a/src/compiler/js-context-specialization.cc
+++ b/src/compiler/js-context-specialization.cc
@@ -77,9 +77,6 @@ Reduction JSContextSpecialization::ReduceJSLoadContext(Node* node) {
   // Success. The context load can be replaced with the constant.
   // TODO(titzer): record the specialization for sharing code across multiple
   // contexts that have the same value in the corresponding context slot.
-  if (value->IsConsString()) {
-    value = String::Flatten(Handle<String>::cast(value), TENURED);
-  }
   Node* constant = jsgraph_->Constant(value);
   ReplaceWithValue(node, constant);
   return Replace(constant);