Simplify CI build for opensourcing

[tristanlabelle]

Most of the CI complexity came from when we were analyzing why webdriver-swift was failing to launch winappdriver.exe in CI, which we found has to do with a combination of the way XCTest uses the Win32 job api and how we were launching winappdriver.exe with handle inheritance.

• Use the released Swift 5.8 version.
• Remove screenshot taking and uploading steps.
• Remove crash reporting and its dependency on the arc repo.
• Remove long paths configuration, which is not needed in other similar repos.
• Remove special logic to ensure the output is flushed and captured (we can revive this if it's ever needed again).

[jeffdav]

The screenshot stuff wasn't working anyway, as far as I could tell. :P

[tristanlabelle]

The screenshot stuff wasn't working anyway, as far as I could tell. :P

It was calling a ps1 script that wasn't checked in (anymore?)