Unable to use `phpenv config-rm` on s390x or arm64

I’m attempting to run PHP builds on the standard amd64 architecture, as well as s390x and arm64, but I’m running into issues with the behavior of phpenv config-rm when trying to disable the Xdebug extension.

For PHP 7.2, 7.3, and 7.4 on the standard amd64 architecture, the following command works and disables Xdebug:

phpenv config-rm xdebug.ini

However, with the same PHP versions on s390x and arm64, this command exits with a non-zero status and the message:

phpenv: no such command `config-rm'

Here’s the relevant output in the jobs:

(If you wonder why I’m checking the $TRAVIS_EVENT_TYPE for cron, it’s because I want to disable Xdebug for standard push/api builds, but I want Xdebug enabled for cron builds. This is so the push builds can complete faster, without attempting to generate code coverage reports, while a daily build runs to generate coverage reports.)