[wasm] Use a Managed<WasmModule> to hold metadata about modules.

test/fuzzer/wasm-section-fuzzers.cc

Index: test/fuzzer/wasm-section-fuzzers.cc
diff --git a/test/fuzzer/wasm-section-fuzzers.cc b/test/fuzzer/wasm-section-fuzzers.cc
index 7b7d0e11459578fbac67a3372830064701f9bef8..1ef5967aa859213c369c1863b7c3056e7511fb3f 100644
--- a/test/fuzzer/wasm-section-fuzzers.cc
+++ b/test/fuzzer/wasm-section-fuzzers.cc
@@ -57,7 +57,7 @@ int fuzz_wasm_section(WasmSectionCode section, const uint8_t* data,
   ErrorThrower thrower(i_isolate, "decoder");
 
   std::unique_ptr<const WasmModule> module(testing::DecodeWasmModuleForTesting(
-      i_isolate, &zone, &thrower, buffer.begin(), buffer.end(), kWasmOrigin));
+      i_isolate, &thrower, buffer.begin(), buffer.end(), kWasmOrigin));
 
   return 0;
 }