[stubs] Port KeyedStoreIC_Megamorphic stub to Turbofan

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 1400 matching lines @@
     "src/ic/handler-compiler.h",
     "src/ic/handler-configuration-inl.h",
     "src/ic/handler-configuration.h",
     "src/ic/ic-compiler.cc",
     "src/ic/ic-compiler.h",
     "src/ic/ic-inl.h",
     "src/ic/ic-state.cc",
     "src/ic/ic-state.h",
     "src/ic/ic.cc",
     "src/ic/ic.h",
+    "src/ic/keyed-store-generic.cc",
+    "src/ic/keyed-store-generic.h",
     "src/ic/stub-cache.cc",
     "src/ic/stub-cache.h",
     "src/icu_util.cc",
     "src/icu_util.h",
     "src/identity-map.cc",
     "src/identity-map.h",
     "src/interface-descriptors.cc",
     "src/interface-descriptors.h",
     "src/interpreter/bytecode-array-builder.cc",
     "src/interpreter/bytecode-array-builder.h",
@@ skipping 1548 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }