Auto generate test config files

This change allows one to run atest <module name>. The TradeFed test
config file will be automatically created in testcases directory based
on the settings.

Bug: 69929803, 69932044
Test: m -j NotificationStressTests libminijail_test
add following lines in notificationtests/Android.mk,
before "include $(BUILD_PACKAGE)"
LOCAL_COMPATIBILITY_SUITE := general-test

Change-Id: Ib5e9cd152d957b5d5beb6ed23a899a021a7e06d6