VTY tests: fill DB before running test

Create a test_subscriber.vty.sql file with a dummy entry that has the
ID 100. All entries created in test_subscriber.vty have an ID > 100
now. This will be used in follow-up commit [1] to create a database
entry with an invalid IMEI value to test the related error handling
code path (that entry could not be created through the VTY).

[1]: change-id I1af7b573ca2a1cb22497052665012d9c1acf3b30
     "VTY: integrate IMEI"

Related: OS#3733
Change-Id: I48a3a503d7ca96798e2d5f70429b5fc36393420e
3 files changed