Revert Visual Studio Default to the desktop compiler

[KevinRansom]

Here it is identified that the Coreclr compiler startup time is slower: #11907

So we should go back to using the ngened desktop compiler, until the performance issue is addressed.

It's a regression in the performance of Visual Studio, even though the coreclr has behaved this way for a long time.

[vzarytovskii]

This is done