Remove unused code from hidden API CTS tests

We do not have class entries in the hidden API lists any longer.
Remove the code that deals with them from the CTS test.

Test: cd cts/tests/signature && ./runSignatureTest.sh
Merged-In: I8645a2cfec286b6a3f28878cb4420afd1b87d3ec
Change-Id: I8645a2cfec286b6a3f28878cb4420afd1b87d3ec
(cherry picked from commit 1b3b1497b50eec7ff81c87517f20f4bb78065dc4)
1 file changed