Make is not setting PreoptBootJars, pass the value computed in
Soong back to Make.
Test: m checkbuild
Change-Id: Ie3db926df9c5d6bf18db1003b95823c7566800a9
Refactor dexpreopt_bootjars.go so that buildBootImage can be called
with a bootImageConfig to create rules to build the boot image in
preparation for building multiple boot images.
Test: m checkbuild
Change-Id: I7ba40a0988c8acbd6c1ee4e36f4bbb34fb4e2d24