Revert of Remove SIMD.js from V8.

src/crankshaft/x64/lithium-codegen-x64.cc

Index: src/crankshaft/x64/lithium-codegen-x64.cc
diff --git a/src/crankshaft/x64/lithium-codegen-x64.cc b/src/crankshaft/x64/lithium-codegen-x64.cc
index e520bf79b6b4aecdacc3db03c00f77558b1c7eaf..7b0443ebf92ca2c9782cdcc30280226b46624ac3 100644
--- a/src/crankshaft/x64/lithium-codegen-x64.cc
+++ b/src/crankshaft/x64/lithium-codegen-x64.cc
@@ -2065,6 +2065,12 @@
         __ j(equal, instr->TrueLabel(chunk_));
       }
 
+      if (expected & ToBooleanHint::kSimdValue) {
+        // SIMD value -> true.
+        __ CmpInstanceType(map, SIMD128_VALUE_TYPE);
+        __ j(equal, instr->TrueLabel(chunk_));
+      }
+
       if (expected & ToBooleanHint::kHeapNumber) {
         // heap number -> false iff +0, -0, or NaN.
         Label not_heap_number;
@@ -5189,6 +5195,17 @@
              Immediate((1 << Map::kIsCallable) | (1 << Map::kIsUndetectable)));
     final_branch_condition = zero;
 
+// clang-format off
+#define SIMD128_TYPE(TYPE, Type, type, lane_count, lane_type)       \
+  } else if (String::Equals(type_name, factory->type##_string())) { \
+    __ JumpIfSmi(input, false_label, false_distance);               \
+    __ CompareRoot(FieldOperand(input, HeapObject::kMapOffset),     \
+                   Heap::k##Type##MapRootIndex);                    \
+    final_branch_condition = equal;
+  SIMD128_TYPES(SIMD128_TYPE)
+#undef SIMD128_TYPE
+    // clang-format on
+
   } else {
     __ jmp(false_label, false_distance);
   }