Use graph build and test for PR builds

[dfederm]

Bug

Fixes: N/A

Description

This changes uses the MSBuild graph to build and runs test as part of the graph. This means that build and test is happening concurrently and can save a bunch of time.

From local testing:

Baseline build: 1:15
Graph build: 1:12

Baseline build & test (serial): 3:30
Graph build & test (concurrent): 1:21

Pipeline numbers: TBD

PR Checklist

• Meaningful title, helpful description and a linked NuGet/Home issue
• Added tests
• Link to an issue or pull request to update docs if this PR changes settings, environment variables, new feature, etc.