[wasm] Don't initialize WebAssembly if WebAssembly is disabled

Bug: chromium:1197703
Change-Id: I36fd8b6ef4105e7deab9617d3cd1f2eb44e08171
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2850650
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74185}

src/api/api.cc

@@ -8997,10 +8997,12 @@ CALLBACK_SETTER(WasmExceptionsEnabledCallback, WasmExceptionsEnabledCallback,
 
 void Isolate::InstallConditionalFeatures(Local<Context> context) {
 #if V8_ENABLE_WEBASSEMBLY
+  if (i::FLAG_expose_wasm) {
     v8::HandleScope handle_scope(this);
     v8::Context::Scope context_scope(context);
     i::WasmJs::InstallConditionalFeatures(reinterpret_cast<i::Isolate*>(this),
                                           Utils::OpenHandle(*context));
+  }
 #endif  // V8_ENABLE_WEBASSEMBLY
 }