[wasm] Call a runtime function for a MemorySize instruction.

test/cctest/wasm/test-run-wasm-module.cc

Index: test/cctest/wasm/test-run-wasm-module.cc
diff --git a/test/cctest/wasm/test-run-wasm-module.cc b/test/cctest/wasm/test-run-wasm-module.cc
index 766f5d03dba17cf0cb4b2fe6e1a86b7a7f1d4c4c..394a72367740720743895158b4965f9aef930cf8 100644
--- a/test/cctest/wasm/test-run-wasm-module.cc
+++ b/test/cctest/wasm/test-run-wasm-module.cc
@@ -253,6 +253,21 @@ TEST(Run_WasmModule_Serialization) {
   }
 }
 
+TEST(MemorySize) {
+  // Initial memory size is 16, see wasm-module-builder.cc
+  static const int kExpectedValue = 16;
+  TestSignatures sigs;
+  v8::internal::AccountingAllocator allocator;
+  Zone zone(&allocator);
+
+  WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
+  WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
+  ExportAsMain(f);
+  byte code[] = {WASM_MEMORY_SIZE};
+  f->EmitCode(code, sizeof(code));
+  TestModule(&zone, builder, kExpectedValue);
+}
+
 TEST(Run_WasmModule_MemSize_GrowMem) {
   // Initial memory size = 16 + GrowMemory(10)
   static const int kExpectedValue = 26;