[turbofan] We cannot unconditionally flatten cons strings in the JSGraph.

src/compiler/js-graph.cc

Index: src/compiler/js-graph.cc
diff --git a/src/compiler/js-graph.cc b/src/compiler/js-graph.cc
index 9db67b5f7c30126ee940e2f885ab0feb4bd087f3..a2ea092e126fb2f679372bacdc0e5b530c10d3f5 100644
--- a/src/compiler/js-graph.cc
+++ b/src/compiler/js-graph.cc
@@ -12,9 +12,7 @@ namespace internal {
 namespace compiler {
 
 Node* JSGraph::ImmovableHeapConstant(Handle<HeapObject> value) {
-  if (value->IsConsString()) {
-    value = String::Flatten(Handle<String>::cast(value), TENURED);
-  }
+  // TODO(bmeurer): Flatten cons strings here before we canonicalize them?
   return graph()->NewNode(common()->HeapConstant(value));
 }