Improve ApexServiceNoHashtreeApexActivationTest#NewSessionDoesNotImpactActivePackage

Also check that active hashtree is not deleted when new version of apex
is staged.

Test: apexservice_test
Bug: 145670581
Change-Id: I54ac077b92a5a31918c78a1c4f90b4538a72798f
Merged-In: I54ac077b92a5a31918c78a1c4f90b4538a72798f
(cherry picked from commit 2b1c19a07463a65ea49f3b0bdf514f195e62e194)
1 file changed