zygote: use libcutils to allocate JIT memory

Original motivation for opening /dev/ashmem directly in zygote was to
avoid binder hop of ashmem_create_region() talking to ashmemd.

Ashmemd is no more, and ashmem_create_region() opens an ashmem fd
in-process. See aosp/q/topic:remove_ashmemd, b/139855428. So we replace
raw /dev/ashmem access with corresponding libcutils API.

Test: m test-art-host-gtest-jit_memory_region_test
Test: boot taimen
Change-Id: Id6cadc88ef6197ba833824423fc96ccbabcfc499
1 file changed