use dalvik.vm.boot-dex2oat-threads inside microdroid

Previously, all dalvik.vm.* properties were not used / ignored in
Microdroid. However this change makes use of
dalvik.vm.boot-dex2oat-threads which controls the concurrency level of
dex2oat.

Specifically, on the host-side, the number of vCPUs in the compos VM is
configured from the system property having the same name. Then inside
the compos VM, compsvc which runs in the compos domain, sets the system
property to be the number of vCPUs in the VM. In other words, the system
properties get the same value both in the host and the guest VMs. Then
finally, the dex2oat process running inside the VM reads the system
property and configures its concurrency level accordingly.

Bug: 197358423
Test: run compos

Change-Id: I8d2394a7192a7b55a910f317e12e2b1f60b89636
4 files changed