Make maps in monomorphic IC stubs weak.

src/lithium-codegen.cc

Index: src/lithium-codegen.cc
diff --git a/src/lithium-codegen.cc b/src/lithium-codegen.cc
index 1fbb2516e8027d335d0821dfcf231c884ae73e38..3cd16db37da9ad5329d897b1d0d967693c16db5d 100644
--- a/src/lithium-codegen.cc
+++ b/src/lithium-codegen.cc
@@ -211,7 +211,7 @@ void LCodeGenBase::RegisterWeakObjectsInOptimizedCode(Handle<Code> code) {
   NoWeakObjectVerificationScope disable_verification_of_embedded_objects;
 #endif
   for (int i = 0; i < maps.length(); i++) {
-    maps.at(i)->AddDependentCode(DependentCode::kWeaklyEmbeddedGroup, code);
+    maps.at(i)->AddDependentCode(DependentCode::kWeakCodeGroup, code);
   }
   for (int i = 0; i < objects.length(); i++) {
     AddWeakObjectToCodeDependency(isolate()->heap(), objects.at(i), code);