Fix the version specifier for the new p4python arm64 builds.
Review Request #12023 — Created Jan. 31, 2022 and submitted — Latest diff uploaded
My previous change to include our custom p4python arm64 builds wasn't
right. The wrong specifier was being used to match arm64. I've fixed it
to useplatform_machineand notplatform_system, and made that
conditional on running on Darwin.
Tested a clean installation. Got the right builds on M1.