[wasm] Fix PC not aligned on s390 debug test case

 DCHECK(IsAligned(addr, alignof(T))) is false on s390 debug simulator test
 case. So copy to an aligned buffer and we can relocate the serialized code.

Change-Id: I8e4ad9ff25fd9a9e5478831250ff741c3e72a86f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1822860Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Clemens Backes [né Hammacher] <clemensb@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#63990}

src/wasm/wasm-serialization.cc

@@ -359,7 +359,7 @@ void NativeModuleSerializer::WriteCode(const WasmCode* code, Writer* writer) {
   writer->WriteVector(code->source_positions());
   writer->WriteVector(Vector<byte>::cast(code->protected_instructions()));
 #if V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM || \
-    V8_TARGET_ARCH_PPC
+    V8_TARGET_ARCH_PPC || V8_TARGET_ARCH_S390X
   // On platforms that don't support misaligned word stores, copy to an aligned
   // buffer if necessary so we can relocate the serialized code.
   std::unique_ptr<byte[]> aligned_buffer;