Do Not Try To Install Benchmark Dependencies If Already Done

Currently we install each benchmark's requirements every time we run the benchmarks, which adds to the time it takes. If we know they are already installed then we can skip that.

Possible solutions:

• only install requirements when a venv is created
  • for the common venv, we'd need to track (in a file) which benchmarks have been done already
• only install requirements if not done already for the venv
  • track with a file (e.g. <venvroot>/.installed)
  • use a file to track what has already been installed in the venv
  • use pip freeze (or similar) to identify what has been installed already (requires the ability to verify requirements)

All that said, I'm not sure this alone is worth the effort. It might be worth it if combined with #157.

首先追踪 benchmark 要求的安装位置，以及通用和每个 benchmark 独立的虚拟环境是如何创建的。比较跟踪已安装要求与检查环境这两种方式，包括与 issue #157 的交互。当依赖项已经可用时，重复运行 benchmark 会跳过相关工作，同时不损害依赖项的正确性，即表示完成。