According to a conversation @Dzahn and myself held at -releng yesterday related to https://gerrit.wikimedia.org/r/#/c/operations/puppet/+/528730 we've detected that foreachwiki and foreachwikiindblist does force RUNNER=php so it somewhat moots the point of T195392.
I couldn't find much for foreachwiki but foreachwikiindblist does indeed use RUNNER=php on its code: https://github.com/wikimedia/puppet/blob/production/modules/scap/files/foreachwikiindblist