Revert "Fix error in unrecognized register name handling for "SBFrame.register"" (#88468)

Reverts llvm/llvm-project#88047. TestFrames.py is failing on x86_64
GreenDragon:
https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/lldb-cmake/983/
GitOrigin-RevId: 9f14914753599f3879e4c273191959e2f1b3632c
2 files changed