Some of ART tests fail to mmap memory unless
LibartImgDeviceBaseAddress() is further lowered.
Test: booted MIPS32R2 in QEMU
Test: booted MIPS64 (with 2nd arch MIPS32R6) in QEMU
Test: test-art-target-gtest
Test: testrunner.py --target --optimizing
Test: repeat all of the above in configurations
ART_READ_BARRIER_TYPE=TABLELOOKUP,
ART_USE_READ_BARRIER=false
Test: repeat the above tests on CI20
Change-Id: I48cd9d8074e07073cc6abb2153660e00017b9e6b