[wasm] Fix bounds check for zero initial memory.

test/mjsunit/wasm/import-memory.js

Index: test/mjsunit/wasm/import-memory.js
diff --git a/test/mjsunit/wasm/import-memory.js b/test/mjsunit/wasm/import-memory.js
index 30c1acc25a914e1074922bf760b11c300c197326..9f4e308ea8b1b4abf523bfaadf7b0943f2792d15 100644
--- a/test/mjsunit/wasm/import-memory.js
+++ b/test/mjsunit/wasm/import-memory.js
@@ -80,3 +80,34 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
     }
   }
 })();
+
+(function ValidateBoundsCheck() {
+  print("Validate bounds check");
+  let memory = new WebAssembly.Memory({initial: 1, maximum: 5});
+  assertEquals(kPageSize, memory.buffer.byteLength);
+  let i32 = new Int32Array(memory.buffer);
+  let builder = new WasmModuleBuilder();
+  // builder.addImportedMemory("mine");
+  builder.addImportedMemory("mine");
+  builder.addFunction("load", kSig_i_i)
+      .addBody([kExprGetLocal, 0, kExprI32LoadMem, 0, 0])
+      .exportFunc();
+  builder.addFunction("store", kSig_i_ii)
+      .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32StoreMem, 0, 0,
+                kExprGetLocal, 1])
+      .exportFunc();
+  var offset;
+  let instance = builder.instantiate({mine: memory});
+  function load() { return instance.exports.load(offset); }
+  function store(value) { return instance.exports.store(offset, value); }
+
+  for (offset = 0; offset < kPageSize -3; offset+=4) {
+    store(offset);
+  }
+  for (offset = 0; offset < kPageSize - 3; offset+=4) {
+    assertEquals(offset, load());
+  }
+  for (offset = kPageSize - 3; offset < kPageSize + 4; offset++) {
+    assertTraps(kTrapMemOutOfBounds, load);
+  }
+})();