Add internal tests for WASI threads. These tests are run in addition to the ones in the proposal: https://github.com/WebAssembly/wasi-threads/tree/main/test/testsuite. The purpose is to test additional and more complex scenarios.
Update CI to run extended WASI threads tests included in the proposal https://github.com/WebAssembly/wasi-testsuite/tree/prod/testsuite-all/tests/proposals/wasi-threads