Fix platform detection logic (#1470)
Fix platform detection logic (#1470)

Checking the OS with `platform == "macos"` and `platform == "windows"`
stopped working with the introduction of macos_arm64 and windows_arm64.

Progress towards
https://github.com/bazelbuild/continuous-integration/issues/1371
bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration