PR Summary

• Update to .NET 6 Preview 6
• Update to use crossgen2 instead of crossgen as crossgen.exe is not available in preview 6.
• Fix CA1845 issues
• Add workaround for issues https://github.com/dotnet/sdk/issues/18995 and Crossgen2 nuget package is not pulled when dotnet restore is done dotnet/sdk#18999
• Disable Test-Connection MTUSize tests due to [Regression] Ping.SendPingAsync API throws SocketException: Message too long exception on .NET 6 Preview 6 dotnet/runtime#55961
• Disable tests due to BigInteger.TryParse incorrectly parses "80000000" from hex as -4294967295 dotnet/runtime#54251
• Update startup test to remove System.IO.FileSystem.dll as it is not loaded anymore.

PR Context

Update to use crossgen2 instead of crossgen

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: or [ WIP ] to the beginning of the title (the WIP bot will keep its status check at Pending while the prefix is present) and remove the prefix when the PR is ready.
• Breaking changes
  • None
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s):
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
  • I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
  • OR
  • I have considered the user experience from a tooling perspective and opened an issue in the relevant tool repository. This may include:
    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode
      (which runs in a different PS Host).
      • Issue filed:
    • Impact on Completions (both in the console and in editors) - one of PowerShell's most powerful features.
      • Issue filed:
    • Impact on PSScriptAnalyzer (which provides linting & formatting in the editor extensions).
      • Issue filed:
    • Impact on EditorSyntax (which provides syntax highlighting with in VSCode, GitHub, and many other editors).
      • Issue filed: