[wasm] Remove left-over of memory masking

Memory masking was removed in https://crrev.com/c/3045704. The comment
and CHECK referred to the code to compute the memory mask, so it does
not apply any more. Thus remove it as well.

R=thibaudm@chromium.org

Bug: v8:12425
Change-Id: If11af4f2179dc01003ea6b532c6ac5696d6fa475
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3592953Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80043}

src/wasm/wasm-objects.cc

@@ -1156,15 +1156,8 @@ bool WasmInstanceObject::EnsureIndirectFunctionTableWithMinimumSize(
 
 void WasmInstanceObject::SetRawMemory(byte* mem_start, size_t mem_size) {
   CHECK_LE(mem_size, wasm::max_mem_bytes());
-#if V8_HOST_ARCH_64_BIT
   set_memory_start(mem_start);
   set_memory_size(mem_size);
-#else
-  // Must handle memory > 2GiB specially.
-  CHECK_LE(mem_size, size_t{kMaxUInt32});
-  set_memory_start(mem_start);
-  set_memory_size(mem_size);
-#endif
 }
 
 const WasmModule* WasmInstanceObject::module() {