These weak symbols are no longer necessary because we no longer
need to statically link libvndksupport.
Furthermore, these symbols are not really optional when libvndksupport is
dynamically linked. When the library is linked with --as-needed the linker
may drop the reference to libdl_android.so, which leads to a failure to boot.
Bug: 146456667
Change-Id: I4d2290d8d0206e0d89665d4d872a7c53b3e1531b
Also: remove an obsolete comment from linker_test.cpp. The test program is
at /data/nativetest[64]/libvndksupport-tests/libvndksupport-tests, which
may will be in the system or legacy configuration, and either the "sphal"
or "default" namespace will be visible.
Bug: none
Test: run libvndksupport-tests, device boots
Change-Id: I5e33e5bf1402a0368e046b03827c216789b02c96