Build jemalloc for host, too.

We build both static and dynamic libjemalloc and libjemalloc_jet for
the host. For the target, only the static libraries are built, just
as before.

Disable sanitizer for the unit/integration tests on the host.

Bug: 113365582

Test: 'mmma external/jemalloc', verify that it builds the same target
libraries, verify it builds host libraries and they can be used to
build ckati.

Change-Id: I84212d0c51995aab25f83deb087d1670ddfb00a8