Moves the download of historic test runtimes out of `bazel/workspace_status.py` and into the `resmoke_suite_test` macro.

This enables pulling stats per-test target rather than per Evergreen task, allowing resmoke to better balance the runtime of test shards.

This also avoids extra runtime in `bazel/workspace_status.py` which is paid for in every `bazel build/test` command, regardless of what is being built/tested.