Investigate a mode in msbuild that reduces the actions during build

[marcpopMSFT]

For the Live Unit Test scenario, we've been requested to provide a mode where we skip all checks and trust the caller to provider the information as to what has changed (ie trust VS) and treat that information as that output of the up-to-date check.

[marcpopMSFT]

Need to follow up with LUT team to get clarification on the ask and the data they have that indicates the up to date checks are slow.

[marcpopMSFT]

From conversations, some options here for a LUT mode would exclude PDB generation, potentially turn off some analyzers, diable some artifact generation (nuget/vsix/xml docs that wouldn't be used in test). Still in discussions on what this looks like.

[marcpopMSFT]

This is tracked separately and driven by the LUT team.