Visual Studio PackageReference partial restore, solution based up to date check

[nkolev92]

Bug

Fixes: NuGet/Home#9513
Regression: No

• Last working version:
• How are we preventing it in future:

Fix

Details:
Design at NuGet/Home#9564. Recommended you read that before reviewing. Specifically the https://github.com/NuGet/Home/blob/dev-nkolev92-partialrestore/designs/VisualStudio-PartialRestoreOptimization.md#solutionuptodatechecker section.

Pulling up the project level no-op to a solution level one with a few additional assumptions.

Some numbers:

Product Name	VS 2019.5.5	VS 2019.6.6 P6	VS 2019.7 prototype.	VS 2019.7 prototype without legacy projects		VS 2019.6.6 P6	VS 2019.7 prototype.	VS 2019.7 prototype without legacy projects
Machine	PC	PC	PC	PC		Laptop	Laptop	Laptop
	1.6804014	1.6156941	0.1379934	0.4676703		1.9918262	0.8003277	0.9779166
	2.0785128	1.5657122	0.2868548	0.5782298		2.1794812	0.2650475	0.7390993
	1.57547	1.4855428	0.2480139	0.465401		2.1542342	0.1249913	0.5509775
	1.6408717	1.3002356	0.0922059	0.3999576		2.1923273	0.1813558	0.9208276
	1.9922636	1.6086686	0.2854186	0.4808997		2.7275282	0.3690762	0.8273464
Average	1.7935039	1.51517066	0.21009732	0.47843168		2.24907942	0.3481597	0.80323348
Standard Deviation	0.202169749	0.117026633	0.080124946	0.057287945		0.249861076	0.240594561	0.150113474
Compared to earlier releases		-15.51896486	-86.13375209	-68.4239081			-84.51990193	-64.28612201
		16.6 to 16.5	16.7 to 16.6	16.7 prototype to 16.6			16.7 to 16.6	16.7 prototype to 16.6

Improvements of 60%+ in the NuGet.sln.

I will do numbers on more solutions as time progresses, but I am confident that the numbers will be comparable. Especially for SDK based projects.

Testing/Validation

Tests Added: Yes
Reason for not adding tests:
Validation:

[nkolev92]

🔔

I'll do a rebase to resolve the conflicts, but it won't change the meat of the work (it's not in solutionrestorejob).

[nkolev92]

Resolved the merge conflicts.

[zivkan]

After rushing through a review of this, I don't understand it super well, but at the same time I didn't see anything that's a real concern to me.

[nkolev92]

🔔 @dominoFire @erdembayar
In case you have any feedback.

I just realized that @srdjanjovcic was not on the requested review list so adding him. :)