Various fixes for multi-level lookup

[gkhanna79]

We need to do the following:

1. Disable looking up user-profile and only lookup dotnet EXE location and global location.
2. For patch roll forward for SharedFX, pickup the highest version from across all locations.

CC @davidfowl @nguerrera @ramarag @piotrpMSFT @blowdart @morganbr

[gkhanna79]

CC @eerhardt

[gkhanna79]

@ramarag Do you think we can get this change in today? I would like to have it bake in before Escrow next week.

[natemcmaster]

Can I ask what's driving this change? Unfortunately, we updated ASP.NET Core's build system about a month ago to use %USERPROFILE% to keep our command-line builds and VS experience in sync. IIUC we can't do that anymore once this is in as scripts don't have write-permissions to global and VS doesn't look at local.

cc @mikeharder @rynowak @davidfowl @pranavkm

[gkhanna79]

Please follow up offline with @davidfowl to understand the motivation and how the scenario will continue working.

[gkhanna79]

Closing since fixed.