Extending idbobjectstores_add Web platform test coverage

Most tests in web_tests/external/wpt/IndexedDB/ are only testing behavior in window environment.
We are extending the the tests to cover different workers (dedicated, serviceworker, sharedworker).
Tests related to idbobjectstores_add.htm have been extended.

Bug: 41455766

extended idbobjectstores_add.html related tests

Change-Id: Icf3a67d0263add7ecede8a257f03834323a8192a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5311879


Reviewed-by: Brandon Maslen <brandm@microsoft.com>
Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Sneha Agarwal <snehagarwal@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1263715}