When I click on the Maps icon on either my iPhone or iPad running iOS 8.4 beta or my wife's devices running iOS 8.3, Apple Maps comes up. What happens when you touch the Google Maps icon?
Admittedly the Apple Maps UI looks somewhat like that of Google Maps but there are distinct differences. For one thing in Google Maps the word "Google" appears in gray in the search bar near the top of the screen. If Google Maps is actually opening when you touch the Maps icon then try holding down the Home button (the round one at the bottom of the screen) and the Hold or Off button the bar at the top left of the iPad when it is held in the portrait position) until your iOS device reboots. That should restore normal operation.
