[llvm] [llvm-exegesis] Use hex values when parsing memory mappings (PR #72620)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Additionally, we might want to do the same for the memory definition sizes. That would probably be for the best given everything else will be in hex after this point for consistency purposes.

https://github.com/llvm/llvm-project/pull/72620