Fixing couple of typos in cpp humaneval.
Example 121: The entry point and the prompt calls the function `solution` but the signature calls it `solutions`
Example 156: The entry point and the prompt calls the function `int_to_mini_romank` but the signature calls it `int_to_mini_roman`
This change makes them consistent to humaneval in other langaugaes.
Rename data/cpp/data/humanevalbugs.jsonl to data/cpp/data/humanevalpack.jsonl
