WebAssembly tests run with Playwright

[ilonatommy]

Following suggestion in microsoft/playwright#32897 (comment), we would like to shift the responsibility of managing chromium to the testing framework in WebAssembly tests. We can do it easily in Wasm.Build.Tests where we utilize Playwright. However, in library tests we are using Selenium. Selenium does not provide management over installing and locating the browser.
To keep all the WASM tests running on the same browser version, we would like to switch to Playwright in the library tests as well. This PR tries to achieve it, without loosing the original functionalities.

[ivanpovazan]

Would this resolve #974 ?

[ilonatommy]

Yes, but the original reason was to fix dotnet/runtime#107771 by allowing default chromium in WasmBuildTests. If we do it, we would like to keep browser versions in line across our tests (both WasmBuildTest run by runtime and library tests run by xharness).