Add a comment for dotnet/project-system#2454 workaround (#4036)
Add a comment for dotnet/project-system#2454 workaround (#4036)

...so that we know it will be safe to delete at some point in the
future.
shrah/corert,yizhang82/corert,gregkalapos/corert,yizhang82/corert,gregkalapos/corert,shrah/corert,gregkalapos/corert,yizhang82/corert,shrah/corert,shrah/corert,yizhang82/corert,gregkalapos/corert