Use d8's writeFile in test_split_module. NFC (#24082)

Author: sbc100

test/other/test_split_module.post.js

@@ -5,12 +5,14 @@ function saveProfileData() {
     var offset = _malloc(len);
     var actualLen = __write_profile(offset, len);
     var profile_data = HEAPU8.subarray(offset, offset + len);
-    if (typeof fs === 'undefined') {
-      // TODO: Use D8's writeFile when
-      // https://chromium-review.googlesource.com/c/v8/v8/+/4159854 lands.
-      console.log(JSON.stringify(Array.from(profile_data)));
-    } else {
+    if (typeof writeFile !== 'undefined') {
+      console.log('using writeFile')
+      writeFile('profile.data', profile_data);
+    } else if (typeof fs !== 'undefined') {
+      console.log('using fs.writeFileSync')
       fs.writeFileSync('profile.data', profile_data);
+    } else {
+      console.log(JSON.stringify(Array.from(profile_data)));
     }
     console.log('profile size is', actualLen, 'bytes (allocated', len, 'bytes)');
     console.log('wrote profile data')

test/test_other.py

@@ -13373,12 +13373,7 @@ def test_split_module(self, customLoader, jspi, opt):
       self.require_jspi()
       self.emcc_args += ['-g', '-sJSPI_EXPORTS=say_hello']
     self.emcc_args += ['-sEXPORTED_FUNCTIONS=_malloc,_free']
-    output = self.do_other_test('test_split_module.c')
-    if self.js_engines == [config.V8_ENGINE]:
-      # TODO remove this when https://chromium-review.googlesource.com/c/v8/v8/+/4159854
-      # lands.
-      # d8 doesn't support writing a file yet, so extract it from the output.
-      create_file('profile.data', bytearray(json.loads(output[output.find('['):output.find(']') + 1])), True)
+    self.do_other_test('test_split_module.c')
     self.assertExists('test_split_module.wasm')
     self.assertExists('test_split_module.wasm.orig')
     self.assertExists('profile.data')