adb-remount-test: do not brick devices that support overlayfs but do not use it

restore() should not run adb enable-verity if device does not
use overlayfs even though it supports it.

Test: adb-remount-test
Bug: 132070014
Change-Id: I55d0e1a87eca9c5f258a1587c844f2a6e4b13b29