Revert "[RISCV] Refactor X60 scheduling model helper classes. NFC. (#151572)"
This reverts commit 969b246c0218a05a0ed0e237f4f92d28554b88c2.
The commit caused ubsan failure:
```
/home/ray/llvm/llvm/lib/TableGen/Record.cpp:1567:41: runtime error: shift exponent 18446744073709551612 is too large for 64-bit type 'uint64_t' (aka 'unsigned long')
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/ray/llvm/llvm/lib/TableGen/Record.cpp:1567:41
```