Revert of Remove SIMD.js from V8.

src/ast/ast-types.cc

Index: src/ast/ast-types.cc
diff --git a/src/ast/ast-types.cc b/src/ast/ast-types.cc
index c5cdc8701fce5fc39b90155f18263153a625c7d9..c50ae272916d70ea386fc9e37ccd23e0fd41d029 100644
--- a/src/ast/ast-types.cc
+++ b/src/ast/ast-types.cc
@@ -195,6 +195,8 @@
     }
     case HEAP_NUMBER_TYPE:
       return kNumber & kTaggedPointer;
+    case SIMD128_VALUE_TYPE:
+      return kSimd;
     case JS_OBJECT_TYPE:
     case JS_ARGUMENTS_TYPE:
     case JS_ERROR_TYPE:
@@ -1296,6 +1298,13 @@
   return i::SmiValuesAre31Bits() ? kUnsigned30 : kUnsigned31;
 }
 
+#define CONSTRUCT_SIMD_TYPE(NAME, Name, name, lane_count, lane_type) \
+  AstType* AstType::Name(Isolate* isolate, Zone* zone) {             \
+    return Class(i::handle(isolate->heap()->name##_map()), zone);    \
+  }
+SIMD128_TYPES(CONSTRUCT_SIMD_TYPE)
+#undef CONSTRUCT_SIMD_TYPE
+
 // -----------------------------------------------------------------------------
 // Instantiations.