Test: vreg_test

Usage: ./vreg_test.sh [-n | --nominal] [-r | --repeatability] [(-v | --verbosity) <verbosity>]

Description:
This test tests basic regulator functionality for a subset of regulators.

Targets: 8660, 7x27, 7x30, 8x50

Notes:
(1) On Android adb shell, busybox installation is required for test to run.
(2) On Android adb shell, debugfs must be mounted at $ANDROID_DATA/debug
