CTS secondary_user: CtsHiddenApiKillswitchDebugClassTestCases

Marks this CTS test module as supporting secondary_user, meaning that
the tests are eligible to be run from a regular Android user other
than the system user (i.e. other than user 0).

Bug: 141773058
Test: module passed with secondary_user params
 (--enable-optional-parameterization --module-parameter secondary_user)

Change-Id: I8626e89d8c6d5bfbf0e644ec00462013c89e74a2