[wasm] Fix bounds check for zero initial memory.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index b44bc06ba36aaff6cbd92c6a6f9a1f928e0f35a7..16c68da45358639c60c1629f849414aed2552ec6 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -352,9 +352,8 @@ void RelocInfo::update_wasm_memory_reference(
   } else if (IsWasmMemorySizeReference(rmode_)) {
     uint32_t current_size_reference = wasm_memory_size_reference();
     DCHECK(old_size == 0 || current_size_reference <= old_size);
-    uint32_t offset = old_size - current_size_reference;
-    DCHECK_GE(new_size, offset);
-    uint32_t updated_size_reference = new_size - offset;
+    uint32_t updated_size_reference =
+        new_size + (current_size_reference - old_size);
     unchecked_update_wasm_memory_size(updated_size_reference,
                                       icache_flush_mode);
   } else {