[dawn][emscripten] Fix promise handling and pass callback.

- Before the code was effectively doing:
    ```
    let ret = resolve(futureId);
    promise.finally(ret);
    ```
  With the lambda wrapping the resolve call, the callback
  only happens after the resolution of the parent promise.

Bug: 358445329
Change-Id: I9aca5e3476b08660780a32cac6d2cb8d70360ed1
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/203420
Reviewed-by: Austin Eng <[email protected]>
Commit-Queue: Austin Eng <[email protected]>
Commit-Queue: Loko Kung <[email protected]>
Auto-Submit: Loko Kung <[email protected]>
Reviewed-by: Shrek Shao <[email protected]>

third_party/emdawnwebgpu/library_webgpu.js

@@ -95,7 +95,7 @@ var LibraryWebGPU = {
 #if ASYNCIFY
       var futureId = futureIdH * 0x100000000 + futureIdL;
       WebGPU._futures[futureId] =
-        new Promise((resolve) => promise.finally(resolve(futureId)));
+        new Promise((resolve) => promise.finally(() => resolve(futureId)));
 #endif
     },
     _waitAnyPromisesList: [],