Have Golem build bootstrap Bionic libraries on target.

Have Golem target build rule (`build-art-target-golem`) build target
bootstrap Bionic libraries (libc, libdl, libm), so that they can be
found by the linker (in `/system/lib(64)`) even if the Runtime APEX is
not available.

This is a temporary change needed until Golem fully supports the
Runtime APEX.

Test: Rely on the ART Buildbot.
Bug: 121117762
Bug: 120266448
Bug: 113373927
Change-Id: Ied2e6ae8d073f45c9f635c96e1823b094c334991