Then cars and computers are made by natural process. Yet the only natural process that has made any is intelligent design. Until you can show an example of them existing without being built, your argument is a non starter.
There is no scientific quandary about whether or not cars and computers are made by natural processes. This misses the point. Like your failure to specify what life is, your failure to specify what intelligence is continues to make your proposed test so much vapor in the wind. This is just a silly way to avoid letting your deponents separate the argument for supernatural ID from the argument for non-supernatural ID, which, of course, you'd prefer remain confused. If it was natural, then biological science hardly changes an iota, because of your experiment. We just learn we want to look, if possible, further in time and space than we at first thought for life's origins.
If life can be developed a lab, than it was developed by natural means, since labs are natural, and it's success or failure, as far a science is concerned, speaks primarily to the success or failure of natural means. You must constrain the test far more rigorously than is humanly possible, for such a tests failure to RULE OUT EVERY POSSIBLE WAY LIFE MIGHT NATURALLY OCCUR, to actually, seriously be taken to have ruled in favor of non-natural means.