Install dexpreopt artifacts of apex system server jars in same partition

e.g. If a system server jar providing apex is installed in /system_ext,
the dexpreopt files of that jar will also be installed in /system_ext.
Currently, all of these artifacts are installed in /system

This behavior will be flag guarded by
RELEASE_INSTALL_APEX_SYSTEMSERVER_DEXPREOPT_SAME_PARTITION. This is
necessary because the ART runtime needs to be updated to look in the new
/system_ext location. Since some release configs build with ART
prebuilts, the runtime in those prebuilt apexes will not have the
additional search path introduced in https://r.android.com/3287191

Test: Verified that "Could not check odex file" does not appear for
service-compos (a system_ext apex systemserver jar)

Bug: 369678122
Change-Id: I752bdc7f5f69226b503800ce25726a211302cb07