[release/7.0] WBT tests disabled, till a new sdk is available

See https://github.com/dotnet/runtime/pull/77549#issuecomment-1297660028

To unblock https://github.com/dotnet/runtime/pull/76939 , the failing tests are being disabled. These should be re-enabled once a new sdk with the fix for https://github.com/dotnet/sdk/pull/28627 becomes available.