[wasm] Remove double check for --experimental-wasm-simd flag

src/wasm/function-body-decoder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/signature.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/bit-vector.h"
 #include "src/flags.h"
 #include "src/handles.h"
@@ skipping 1597 matching lines @@
       case kExprI8x16ShrS:
       case kExprI8x16ShrU: {
         len = SimdShiftOp(opcode);
         break;
       }
       case kExprS8x16Shuffle: {
         len = Simd8x16ShuffleOp();
         break;
       }
       case kExprS128LoadMem:
-        CHECK_PROTOTYPE_OPCODE(simd);
         len = DecodePrefixedLoadMem(kWasmS128, MachineType::Simd128());
         break;
       case kExprS128StoreMem:
-        CHECK_PROTOTYPE_OPCODE(simd);
         len = DecodePrefixedStoreMem(kWasmS128, MachineType::Simd128());
         break;
       default: {
         FunctionSig* sig = WasmOpcodes::Signature(opcode);
         if (sig != nullptr) {
           compiler::NodeVector inputs(sig->parameter_count(), zone_);
           for (size_t i = sig->parameter_count(); i > 0; i--) {
             Value val = Pop(static_cast<int>(i - 1), sig->GetParam(i - 1));
             inputs[i - 1] = val.node;
           }
@@ skipping 661 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   Decoder decoder(start, end);
   return WasmDecoder::AnalyzeLoopAssignment(&decoder, start,
                                             static_cast<int>(num_locals), zone);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8