Dist userdebug_plat_sepolicy.cil to facilitate VTS testing

This is an attempt to cherry-pick
I7629e462d4febd05ebe8a89a7bc00e8724dcb4a4 back to android11-gsi.
That unfortunately isn't possible, so instead implement the
minimum logic to backport the original change.

---

repack_bootimg can use the userdebug_plat_sepolicy.cil artifact to
prepare a debuggable boot image for VTS testing.

(TODO in follow-up) The eliminates the need for GSI
boot-with-debug-ramdisk-*.img, and we can skip building them to
conserve build resources.

Bug: 202129499
Test: m dist && check dist directory has userdebug_plat_sepolicy.cil
Test: Check presubmit artifacts include userdebug_plat_sepolicy.cil
Change-Id: I67bb1f98f0655c4b90643dce7ef425a08468cfef
1 file changed