Backport fast up to date check to 15.3.x

[panopticoncentral]

Customer scenario

When the user requests a build in VS, CPS will call the project system to see if we believe it can skip calling MSBuild. This is faster than running MSBuild and having it determine that everything is up to date.

Bugs this fixes:

Fixes #62

Workarounds, if any

This is a performance optimization, it is not required for functionality, just speed.

Risk

Fast up to date checks carry a level of risk because if the check is wrong, we will either build when we didn't need to, or won't build when we need to. The former situation isn't any worse than what we have now. The latter situation is bad but can be mitigated in several ways:

• The user can elect to perform a Rebuild.
• We are adding a VS option to disable .NET Core project fast up to date checks entirely. (VS Option setting UI coming in a separate PR today.)
• The project can be marked with a DisableFastUpToDateCheck property that will disable the check for that project
• The user can add UpToDateCheckInput and UpToDateCheckOutput items to their project to work around missing checks.

This PR also adds logging to a "Project" output window that should help easily diagnose where problems are.

Performance impact

Build performance should improve, especially for solutions with many .NET Core projects.

Is this a regression from a previous update?

No

[panopticoncentral]

@dotnet-bot retest this please

[panopticoncentral]

@dotnet-bot retest this please

[ebonato]

Hi @panopticoncentral,
This is not only about performance... our builds are failing, as our pre-build scripts aren't triggering our code generators.
At least on build servers, it relies on update check from msbuild only....

https://developercommunity.visualstudio.com/content/problem/46717/disablefastuptodatecheck-in-project-file-no-longer.html?childToView=67043#comment-67043

[panopticoncentral]

@ebonato This PR only affects the project system that is used by .NET Core and .NET Standard projects. If your problem is with a project that is just a .NET Framework project, then this doesn't apply to that situation. If your project was created prior to 2017, which it sounds like it was, then this has no affect on it.