Unplug the refrigerator when the water does not shut off, if the water still runs into the ice maker tray with the refrigerator unplugged, then your water inlet valve is bad.
This is your water inlet valve in the refrigerator section per this video:
This video provides step-by-step repair instructions for replacing the water inlet valve on a Whirlpool refrigerator. Learn more from the experts at Repair Clinic.
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Here's the water inlet valve for your model, the YELLOW one is the ice maker side:
Water Inlet Valve WPW10349187
If the water DOES STOP filling when you unplug the refrigerator, then your ice maker is the culprit, telling the water inlet valve to stay running.
Here's the ice maker kit for your model:
Ice Maker W10882923
It comes with new wiring that you MUST replace as well.
Watch this video:
Let us know how it goes.