test_for is available for all cc_* module types

Sometimes, the ordinary cc_library_* modules need test_for property when
they are part of a bigger cc_test. Instead of propagating the test_for
property from cc_test to its dependencies, this change requires the very
dependency which needs access to the private part of an APEX to
explicitly have the test_for property.

Bug: 161575591
Test: m
Change-Id: Ie1ffe9a60cd2ab02d41bbe5a98225a40392470f6