Retain user Context as local val for the test duration

- Previous impl did not retain as local variable and that can
  lead into the created Context GCed ranmdoly during the test
  and that leads into local broadcast receiver cleared inside the process.
- Keep it as local val for the test duration so that it is not GCed.

Bug: 234014686
Test: atest android.content.pm.cts.PackageManagerShellCommandMultiUserTest
Change-Id: Icd9a67ed4b4ee9f2d4077a8cf2c8259090f7be2a
1 file changed