Test for hidden api enforcement killswitch

Currently, simply verifies that we can access VMRuntime.THE_ONE, which
doesn't prove anything as there is no blacklisting enabled yet.

Refactor JNI parts of hidden API test into cts-signature-common to it can
be used in this test.

(cherry picked from commit d635f8936bb3baad00c4bf5658e3bc7f420a3421 in
master)

Bug: 64382372
Test: $ cts/tests/signature/runSignatureTests.sh
Change-Id: I8c566136dea2a6b5d41d81981d0f1ef88a0a1a5f
12 files changed