[wasm] Make CodeSpaceWriteScope more narrow

This avoids having all code writable while compiling functions. We only
need it writable for copying the code to the NativeModule and for
updating the jump table(s).

R=jkummerow@chromium.org

Change-Id: Ifb212b1cd3f7702fac4b1eb9e7bc7d5b5bd5198a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3063221Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76035}

src/wasm/module-compiler.cc

@@ -1131,7 +1131,6 @@ bool CompileLazy(Isolate* isolate, Handle<WasmModuleObject> module_object,
   }
 
   DCHECK(!native_module->lazy_compile_frozen());
-  CodeSpaceWriteScope code_space_write_scope(native_module);
 
   TRACE_LAZY("Compiling wasm-function#%d.\n", func_index);
 
@@ -1180,8 +1179,12 @@ bool CompileLazy(Isolate* isolate, Handle<WasmModuleObject> module_object,
   }
 
   WasmCodeRefScope code_ref_scope;
-  WasmCode* code = native_module->PublishCode(
-      native_module->AddCompiledCode(std::move(result)));
+  WasmCode* code;
+  {
+    CodeSpaceWriteScope code_space_write_scope(native_module);
+    code = native_module->PublishCode(
+        native_module->AddCompiledCode(std::move(result)));
+  }
   DCHECK_EQ(func_index, code->index());
 
   if (WasmCode::ShouldBeLogged(isolate)) {