On the initial merge of the dotnet/linker commits into dotnet/runtime, we received a bunch of good feedback on places we need to adopt the runtime's build infra. We wanted to keep the initial merge as faithful to the original sources as possible, and make the improvements as follow-up changes for easier code review. Collecting the feedback here to make sure these follow-up items don't get lost:

• Use consistent msbuild version: Linker into runtime2 #78077 (comment)
• Import repo's Directory.Build.props: Linker into runtime2 #78077 (comment)
• Use shared ref assembly infrastructure: Linker into runtime2 #78077 (comment)
• Remove IsPackable which will be set by arcade: Linker into runtime2 #78077 (comment)
• Use shared packaging settings: Linker into runtime2 #78077 (comment) and Linker into runtime2 #78077 (comment)
• Use shared analyzer settings: Linker into runtime2 #78077 (comment) and Linker into runtime2 #78077 (comment)
• Use shared apicompat infrastructure: Linker into runtime2 #78077 (comment)
• Update readme to reflect the move: Linker into runtime2 #78077 (comment)
• Remove unused pipelines: Linker into runtime2 #78077 (comment)
• Use live ilasm: Linker into runtime2 #78077 (comment)
• Remove unnecessary DefineConstants: Linker into runtime2 #78077 (comment)
• Avoid hardcoded package versions: Linker into runtime2 #78077 (comment) and Linker into runtime2 #78077 (comment)
• Don't explicitly reference ref assemblies which are automatically referenced: Linker into runtime2 #78077 (comment)
• Investigate removing illink PATENTS.txt: Linker into runtime2 #78077 (comment)