When setting the mirrored tables config in test/format to the off state by setting "run.mirrors=0" in the CONFIG file, when test/format is run this value will be flipped to "run.mirrors=1" and is evident in the logs of those test runs.

In config_mirrors() function:

    explicit_mirror = config_explicit(NULL, "runs.mirror");
    if (!explicit_mirror && mmrand(NULL, 1, 10) < 9)
        return;

Here a check is done if there is state for mirrored tables is set the test/format CONFIG file, but it does not check whether or not this is turned on or off, just set. This logic will always set it on if there is a configuration for "run.mirrors", even if that specific table is being set to "=0" when we want it off, and we are not able to explicitly turn it off.

Even if the mirrored tables config is not set, mirrored tables will be turned on by default in test/format with a 1 in 5 probability. Not being able to turn off mirrored tables explicitly is an issue.

This ticket is considered done when we are able to turn off the configuration for mirroring in test/format explicitly.