Revert of Remove SIMD.js from V8.

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

Index: src/crankshaft/ppc/lithium-codegen-ppc.cc
diff --git a/src/crankshaft/ppc/lithium-codegen-ppc.cc b/src/crankshaft/ppc/lithium-codegen-ppc.cc
index c465d9a8e207ed991d897ff82ba267b1dffa9203..f870361144063caa6ff9c23dd8aec45869dec247 100644
--- a/src/crankshaft/ppc/lithium-codegen-ppc.cc
+++ b/src/crankshaft/ppc/lithium-codegen-ppc.cc
@@ -2203,6 +2203,13 @@
       if (expected & ToBooleanHint::kSymbol) {
         // Symbol value -> true.
         __ CompareInstanceType(map, ip, SYMBOL_TYPE);
+        __ beq(instr->TrueLabel(chunk_));
+      }
+
+      if (expected & ToBooleanHint::kSimdValue) {
+        // SIMD value -> true.
+        Label not_simd;
+        __ CompareInstanceType(map, ip, SIMD128_VALUE_TYPE);
         __ beq(instr->TrueLabel(chunk_));
       }
 
@@ -5426,6 +5433,17 @@
     __ cmpi(r0, Operand::Zero());
     final_branch_condition = eq;
 
+// 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);                                \
+    __ LoadP(scratch, FieldMemOperand(input, HeapObject::kMapOffset)); \
+    __ CompareRoot(scratch, Heap::k##Type##MapRootIndex);            \
+    final_branch_condition = eq;
+  SIMD128_TYPES(SIMD128_TYPE)
+#undef SIMD128_TYPE
+    // clang-format on
+
   } else {
     __ b(false_label);
   }