Add CTS tests for rebootless APEX updates

Bug: 188062003
Test: atest CtsStagedInstallHostTestCases
Change-Id: I7c18368ba12f79a31656befe3b5a77705e8622e4
Merged-In: I7c18368ba12f79a31656befe3b5a77705e8622e4
(cherry picked from commit d4c1ea447f818d18250207335e4e6cc7511571dd)
5 files changed