If Xcode path is not provided, use the xcode path from xcode-select

[mandel-macaque]

If the user does not provide the xcode path, use the path returned by xcode-select.

That means that we have to set the path to be lazy and change the mono options definition from using a '=' to a ':' so that it is an optional parameter.

[premun]

So this happens here already:

xharness/src/Microsoft.DotNet.XHarness.iOS.Shared/Execution/ProcessManager.cs

Lines 442 to 466 in 3b84a41

	static string DetectXcodePath()
	{
	using var process = new Process();
	process.StartInfo.FileName = "xcode-select";
	process.StartInfo.Arguments = "-p";
	var log = new MemoryLog();
	var stdout = new MemoryLog() { Timestamp = false };
	var stderr = new ConsoleLog();
	var timeout = TimeSpan.FromSeconds(30);
	var result = RunAsyncInternal(process, log, stdout, stderr, timeout).GetAwaiter().GetResult();
	if (!result.Succeeded)
	throw new Exception("Failed to detect Xcode path from xcode-select!");
	// Something like /Applications/Xcode114.app/Contents/Developers
	var xcodeRoot = stdout.ToString().Trim();
	if (string.IsNullOrEmpty(xcodeRoot))
	throw new Exception("Failed to detect Xcode path from xcode-select!");
	// We need /Applications/Xcode114.app only
	return Path.GetDirectoryName(Path.GetDirectoryName(xcodeRoot));
	}

[premun]

I think this is resolved now. Works as expected.