Revert of Remove SIMD.js from V8.

src/code-factory.cc

Index: src/code-factory.cc
diff --git a/src/code-factory.cc b/src/code-factory.cc
index 466d470a4f2cfb0638781b543f913658fbb9fb31..7f4673d9d4d80971593dec94bd3061e9f77cc132 100644
--- a/src/code-factory.cc
+++ b/src/code-factory.cc
@@ -381,6 +381,14 @@
   return make_callable(stub);
 }
 
+#define SIMD128_ALLOC(TYPE, Type, type, lane_count, lane_type) \
+  Callable CodeFactory::Allocate##Type(Isolate* isolate) {     \
+    Allocate##Type##Stub stub(isolate);                        \
+    return make_callable(stub);                                \
+  }
+SIMD128_TYPES(SIMD128_ALLOC)
+#undef SIMD128_ALLOC
+
 // static
 Callable CodeFactory::ArgumentAdaptor(Isolate* isolate) {
   return Callable(isolate->builtins()->ArgumentsAdaptorTrampoline(),