[Feature] Add IQP / IQP-Z support to QDP benchmark latency / throughput pipelines

[viiccwen]

What

Add IQP-family benchmark support to the standard QDP benchmark path:

• qdp/qdp-python/benchmark/benchmark_latency.py
• qdp/qdp-python/benchmark/benchmark_throughput.py
• the synthetic pipeline used by QdpBenchmark / pipeline_runner

This should cover both:

• --encoding-method iqp
• --encoding-method iqp-z

Why

QDP already supports iqp and iqp-z in the core encoder and Python API, but the main benchmark path is still amplitude/angle/basis-centric.