[wasm] add the default dtype for tf.fill (#5656)

[tiandeyu-cs]

Fix the bug #5656

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[tiandeyu-cs]

@googlebot I signed it!

[tiandeyu-cs]

I'm willing to help, but I do not understand the meaning of the test file, and I do not know how to actually run these tests.

Do you have any introduction or tutorial resources that can help me to understand the test configuration? Thank you😄

[jinjingforever]

Hi @tiandeyu-github, thank you! For this, you need to add {startsWith: 'fill '}, (note the extra space after "fill") to the end of the TEST_FILTERS array here. This will ask the WASM backend to run tests whose names start with "fill " which are defined here.

@@ -433,6 +433,7 @@ const TEST_FILTERS: TestFilter[] = [
   {include: 'image.transform'},
   {include: 'batchToSpaceND'},
   {include: 'spaceToBatchND'},
+  {startsWith: 'fill '},
 ];

After that, under the tfjs-backend-wasm directory, run:

$ yarn
$ yarn test

This should eventually start a chrome which will run all the wasm tests. I tried it in the master branch and it complains about Unknown dtype undefined in all the "fill" tests, which should be fixed by your PR.

(If running tests locally on your machine doesn't work due to certain environment setup issues, you could also try pushing it here and check on the cloud build result)

Please give it a try and let me know any problems. Thanks!