[wasm] Encode immediates to Load and Store as varint.

src/wasm/asm-wasm-builder.cc

Index: src/wasm/asm-wasm-builder.cc
diff --git a/src/wasm/asm-wasm-builder.cc b/src/wasm/asm-wasm-builder.cc
index e5a4bb508ff7273daff38943cfb791967caa1d12..fe6abdaaf8bb110e06b434b868d016f6e27ad624 100644
--- a/src/wasm/asm-wasm-builder.cc
+++ b/src/wasm/asm-wasm-builder.cc
@@ -799,9 +799,9 @@ class AsmWasmBuilderImpl : public AstVisitor {
     } else {
       UNREACHABLE();
     }
-    current_function_builder_->EmitWithU8(
-        WasmOpcodes::LoadStoreOpcodeOf(mtype, is_set_op_),
-        WasmOpcodes::LoadStoreAccessOf(false));
+    // TODO(titzer): use special asm-compatibility opcodes?
+    current_function_builder_->EmitWithU8U8(
+        WasmOpcodes::LoadStoreOpcodeOf(mtype, is_set_op_), 0, 0);
     is_set_op_ = false;
     if (size == 1) {
       // Allow more general expression in byte arrays than the spec