Better explanation when missing JAVA_HOME
Better explanation when missing JAVA_HOME

Change-Id: I4d383761426971f3c7581c094937ea40ff7c5ecf
Fixes: 253666550
Test: rename JAVA_HOME dir, run studiow

androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx