[wasm] Fix gc test with lazy compilation

The test-gc cctest loads the WasmCode from the NativeModule and then
executes it. With lazy compilation, the WasmCode object first has to get
generated before it can get loaded.

R=jkummerow@chromium.org

Bug: v8:12852
Change-Id: I83a8a2433ac5d11690c82f07e4ae01ddc979821c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3809811
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82271}

test/cctest/wasm/test-gc.cc

@@ -243,8 +243,7 @@ class WasmGCTester {
                         CWasmArgumentsPacker* packer) {
     WasmCodeRefScope code_ref_scope;
     NativeModule* native_module = instance_->module_object().native_module();
-    WasmCode* code = native_module->GetCode(function_index);
-    Address wasm_call_target = code->instruction_start();
+    Address wasm_call_target = instance_->GetCallTarget(function_index);
     Handle<Object> object_ref = instance_;
     Handle<CodeT> c_wasm_entry =
         compiler::CompileCWasmEntry(isolate_, sig, native_module->module());