Using regular physics a human scaled up that much they would immediately start to collapse into a pulpy sphere of mostly water, which would further collapse into a star. If you ignored the giant human's body pull on itself, then you'd have to look at the Earth pull on the flesh of the giant, trying to put what amounts to a giant hand shaped water balloon inside a planets roshe limit probably won't end well. If we ignore that, then the Earth would be deep inside your hand's gravitational field, so you probably wouldn't need to squeeze, just having your giant hand near the Earth would cause it to rip itself apart. If we ignore all the gravity based physics then the question becomes "How would muscles larger than planets actually work?".
I guess what I'm trying to say here is that to answer your question is "We have to ignore so much physics to make your question even possible that it's kinda meaningless." It's like asking "If ducks were made of cheese how fast could they fly?"