[llvm] [AsmPrinter] Reduce AsmPrinterHandlers virt. fn calls (PR #96785)

[Alexis Engelke via llvm-commits]

aengelke wrote:

NB: supporting multiple debug handlers slightly regresses performance over my initial approach of zero or one debug handlers ([c-t-t](http://llvm-compile-time-tracker.com/compare.php?from=be4a0b21bf3b146a75759ec9b3cfaf8367eef16d&to=9ce05be2903285e1681ced36e5862ad3e155cb17&stat=instructions:u)). I also don't know if DWARF is actually useful for BPF or whether it is just there because it happened to work.

https://github.com/llvm/llvm-project/pull/96785