[wasm] Introduce custom asm.js bytecodes for loads and stores.

src/compiler/wasm-compiler.h

Index: src/compiler/wasm-compiler.h
diff --git a/src/compiler/wasm-compiler.h b/src/compiler/wasm-compiler.h
index c3e599429995b71e4dd22dd05709940a98c931da..31dea0358c16e3e560faaa602c0b1140affe1421 100644
--- a/src/compiler/wasm-compiler.h
+++ b/src/compiler/wasm-compiler.h
@@ -300,6 +300,8 @@ class WasmGraphBuilder {
   Node* BuildI32AsmjsRemS(Node* left, Node* right);
   Node* BuildI32AsmjsDivU(Node* left, Node* right);
   Node* BuildI32AsmjsRemU(Node* left, Node* right);
+  Node* BuildAsmjsLoadMem(MachineType type, Node* index);
+  Node* BuildAsmjsStoreMem(MachineType type, Node* index, Node* val);
 
   Node** Realloc(Node** buffer, size_t old_count, size_t new_count) {
     Node** buf = Buffer(new_count);