Fix HOST_PREFER_32_BITS tests

When HOST_PREFER_32_BITS is set, HOST_ARCH is still x86_64 but art tests
are only built for x86.  Use ART_HOST_ARCH, which will be set to x86,
to find the list of host tests.

Test: m -j HOST_PREFER_32_BITS=true test-art-host-gtest32
Change-Id: I11a9e1b5111c3c06139b44e364fdcd04bb8db4c6
1 file changed