[wasm-simd] Fix generation of s128.store

s128.store should be in the list for generating kStmt, not kWasmS128.
No regression test added because the generated JS file is not helpful
for this bug - the failed assertion is in the fuzzer, not the engine.

Bug: chromium:1061049
Change-Id: I44092fa10c57aeeb34f1c6c5a7d655def31a7363
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2101927Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66692}

test/fuzzer/wasm-compile.cc

@@ -178,6 +178,9 @@ class WasmGenerator {
   // TODO(eholk): make this function constexpr once gcc supports it
   static uint8_t max_alignment(WasmOpcode memop) {
     switch (memop) {
+      case kExprS128LoadMem:
+      case kExprS128StoreMem:
+        return 4;
       case kExprI64LoadMem:
       case kExprF64LoadMem:
       case kExprI64StoreMem:
@@ -614,6 +617,7 @@ void WasmGenerator::Generate<ValueType::kStmt>(DataRange* data) {
       &WasmGenerator::memop<kExprI64AtomicStore8U, ValueType::kI64>,
       &WasmGenerator::memop<kExprI64AtomicStore16U, ValueType::kI64>,
       &WasmGenerator::memop<kExprI64AtomicStore32U, ValueType::kI64>,
+      &WasmGenerator::memop<kExprS128StoreMem, ValueType::kS128>,
 
       &WasmGenerator::drop,
 
@@ -1053,8 +1057,7 @@ void WasmGenerator::Generate<ValueType::kS128>(DataRange* data) {
       &WasmGenerator::simd_op<kExprF64x2Add, ValueType::kS128,
                               ValueType::kS128>,
 
-      &WasmGenerator::memop<kExprS128LoadMem>,
-      &WasmGenerator::memop<kExprS128StoreMem, ValueType::kS128>};
+      &WasmGenerator::memop<kExprS128LoadMem>};
 
   GenerateOneOf(alternatives, data);
 }