[wasm] Fix decoder for null data

test/unittests/wasm/decoder-unittest.cc

Index: test/unittests/wasm/decoder-unittest.cc
diff --git a/test/unittests/wasm/decoder-unittest.cc b/test/unittests/wasm/decoder-unittest.cc
index d1580c3a7d9d99dfb08dc18eb88dece23c334468..fdb353714e5c320bf1d7c36081d2989a0dccdc15 100644
--- a/test/unittests/wasm/decoder-unittest.cc
+++ b/test/unittests/wasm/decoder-unittest.cc
@@ -671,6 +671,13 @@ TEST_F(DecoderTest, ReadI64v_extra_bits_positive) {
   EXPECT_FALSE(decoder.ok());
 }
 
+TEST_F(DecoderTest, FailOnNullData) {
+  decoder.Reset(nullptr, 0);
+  decoder.checkAvailable(1);
+  EXPECT_FALSE(decoder.ok());
+  EXPECT_FALSE(decoder.toResult(nullptr).ok());
+}
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8