[llvm] [X86] Replace hasVirtualTileReg with AMXProgModel (PR #95105)

[Phoebe Wang via llvm-commits]

phoebewang wrote:

> FastPreTileConfig has (without #94989) it's own check whether virtual tile registers exist, it finds this out by iterating over all virtual registers. Functionality should be identical, so no tests are affected.

Sorry, my mistake. I didn't notice FastPreTileConfig also called setHasVirtualTileReg...

https://github.com/llvm/llvm-project/pull/95105