Remove the ability for applications to dlopen() executable code from
their home directory for newer API versions. API versions <= 28 are
uneffected by this change.

Bug: 112357170
Test: cts-tradefed run cts -m CtsRenderscriptTestCases
Change-Id: I1d7f3a1015d54b8610d1c561f38a1a3c2bcf79e4