[wasm] memory size is an uint32_t, not a size_t.

src/wasm/wasm-module.h

Index: src/wasm/wasm-module.h
diff --git a/src/wasm/wasm-module.h b/src/wasm/wasm-module.h
index 615f633a95dd8549909a5e70964276473ecfc93d..6b0cf4d6a0e5a6f525b523ca940f1933868d9758 100644
--- a/src/wasm/wasm-module.h
+++ b/src/wasm/wasm-module.h
@@ -225,7 +225,7 @@ struct WasmModuleInstance {
   std::vector<Handle<Code>> import_code;    // code objects for each import.
   // -- raw memory ------------------------------------------------------------
   byte* mem_start;  // start of linear memory.
-  size_t mem_size;  // size of the linear memory.
+  uint32_t mem_size;  // size of the linear memory.
   // -- raw globals -----------------------------------------------------------
   byte* globals_start;  // start of the globals area.