Add shim APEX for testing rebootless update flow

Test: m com.android.apex.cts.shim.v2_rebootless
Bug: 188062003
Change-Id: Ie785a4286e97e622f9bf1566d189f1a01bcb38d7
Merged-In: Ie785a4286e97e622f9bf1566d189f1a01bcb38d7
(cherry picked from commit 26b2cb0aaf0c816e6a64bb54da8988cddee6b652)
2 files changed