[d8][wasm] Don't enable streaming compilation without async compilation

The --wasm-test-streaming flag enabled streaming compilation after a
check that streaming compilation is not enabled if async compilation is
not enabled. This caused a later check to trigger. With this CL
streaming compilation does not get enabled by --wasm-test-streaming if
async compilation is not enabled.

R=clemensb@chromium.org

Bug: chromium:1082990
Change-Id: Ibe12389beae6a3335d3c8b6039fcea450f25d281
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2202985
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67837}

src/wasm/wasm-js.cc

@@ -2065,8 +2065,15 @@ void WasmJs::Install(Isolate* isolate, bool exposed_on_global_object) {
   // should not be set.
   CHECK_IMPLIES(!FLAG_wasm_async_compilation,
                 isolate->wasm_streaming_callback() == nullptr);
+
   if (FLAG_wasm_test_streaming) {
-    isolate->set_wasm_streaming_callback(WasmStreamingCallbackForTesting);
+    if (FLAG_wasm_async_compilation) {
+      isolate->set_wasm_streaming_callback(WasmStreamingCallbackForTesting);
+    } else {
+      printf(
+          "--wasm-test-streaming gets ignored because async compilation is "
+          "disabled.");
+    }
   }
 
   if (isolate->wasm_streaming_callback() != nullptr) {