Filter generator results by generator IDs for CPU, memory and block listing APIs

[password636]

For listing generator results by openperfclient API: list_cpu_generator_results(), list_memory_generator_results(), list_block_generator_results(), and list_packet_generator_results(), only list_packet_generator_results() can list by generator IDs, i.e. list_packet_generator_results(generator_id). It would be great to add this filtering to other listing APIs.