While I wouldn't say it's "common," there are many lifters who do two-a-days, or even more sessions than that in one day, while training the same muscle or movement many times in one day. Most often you see this with olympic lifters who may ramp to a max squat, for example, 5 different times in a single day (and then do the same thing for 5 more days in a row).
Usually this would be something you'd build up to. At a certain point, when you are already working out 6 or 7 days a week, it becomes necessary to split training sessions into multiple sessions in order continue to add volume/intensity. It's unnecesary for a lifter to go from, for example, 1 chest session a week to 5 of them total (maybe split up over 3 days).
This technique is most often associated with those seeking strength/technique increases--those people trying to put lbs on their lifts. But increasing frequency is beneficial for size as well. The more frequently you can perform a workout with enough volume to elicit a training response, the faster you'll grow, but only so long as you can recover at that higher frequency. Obviously if you could do full body and workout for 8 hours a day every day and somehow recover from that and eat enough food, you'd grow extremely fast. But that obviously is well beyond most people's recovery ability.
In short, increasing frequency is better for gains, but harder on recovery. The more frequency you personally can hit a muscle/movement with and recover from it, the faster the gains will come. Obviously if you're juiced up, then it's easier to use higher frequency because you have increased recovery, but it's not necessary.
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the cortisol spikes which you are referring to won't be an issue.
