Revert "Revert "emulator: create qemu images for system,vendor""
This reverts commit 9b99ddc8.
and add syste-qemu.img to the dependency list of sdk target
BUG: 64235252
Test: build sdk target successfully
(cherry picked from commit f0d50bbe)
Change-Id: I813233c7c3f06eb1eca18aad5ea890a55814eb1b