Thank you very much to the comments above. hippo’s answer snapped me out of my fog and I also did some reading on the various harness libs and such which might come into play another day but for this one, I think (something approximately like) this as a runner is all I need–

use strictures;
use Test::More;

my @config = qw/ PROD DEV /;
for my $env ( @config )
{
    my $test = join "_", $env, "TEST";
    local $ENV{$test} = 1;
    subtest "$env" => sub {
        do "run.t.raw"; # The raw test reports its plan.
    };
}

done_testing( scalar @config );
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