Array length reduction should throw in strict mode if it can't delete an element.

src/ic/handler-compiler.h

Index: src/ic/handler-compiler.h
diff --git a/src/ic/handler-compiler.h b/src/ic/handler-compiler.h
index 2f2d0496350647b5d777ebd76c6448f848545c62..0c571fd34bd23b90933a6e79ff1077b7b5821d63 100644
--- a/src/ic/handler-compiler.h
+++ b/src/ic/handler-compiler.h
@@ -223,7 +223,8 @@ class NamedStoreHandlerCompiler : public PropertyHandlerCompiler {
                                       Handle<Name> name);
   Handle<Code> CompileStoreField(LookupIterator* it);
   Handle<Code> CompileStoreCallback(Handle<JSObject> object, Handle<Name> name,
-                                    Handle<AccessorInfo> callback);
+                                    Handle<AccessorInfo> callback,
+                                    LanguageMode language_mode);
   Handle<Code> CompileStoreCallback(Handle<JSObject> object, Handle<Name> name,
                                     const CallOptimization& call_optimization,
                                     int accessor_index);