Enable/Disable payment processor from summary page only disables live

On the payment processor summary screen (civicrm/admin/paymentProcessor) only the live payment processor is taken into account for enable/disable payment processor and the payment_processor->is_active flag is only set for the live processor via a javascript function.

However, when editing the payment processor on the detail screen (civicrm/admin/paymentProcessor?action=update&id=3) the is_active checkbox will enable/disable both payment processors when it is changed/saved.

Expected behaviour would be to enable/disable live and test from both screens as there is no indication of whether the test processor is enabled or not (and no way to change it).

This manifests itself as an issue when you have a payment processor that is broken and have disabled it via the summary screen, but can't work out why the code for that processor is still being executed (and crashing civicrm in the case of the processor I was testing). This is made worse by the fact that code will still be executed if you have disabled the extension for that processor which leads to a php fatal error if it tries to include any php files from that extension.

I propose that the summary screen is updated to disable/enable both payment processors just like the detail screen does. If this is agreeable I will prepare a patch.

Ref CRM-17998