Implement CACert queries in SecurityController

Cherry-pick note:
testCACertLoader() was flaky, so this cherry-pick contains
two attempted fixes and a CL that disables the test. The original commit
messages of the squashed CLs are below.
Merged-In: I3b9cc3d85c9f49d0a892613b63d1fba184ab647e

Implement CACert queries in SecurityController

Queries are run (on a AsyncTask) when user is switched and when
ACTION_TRUST_STORE_CHANGED is broadcasted. Otherwise, the result is cached
in the SecurityController.

Bug: 37535489
Test: runtest --path frameworks/base/packages/SystemUI/tests/src/com/android/systemui/statusbar/policy/SecurityControllerTest.java
Change-Id: I3b9cc3d85c9f49d0a892613b63d1fba184ab647e

Increase timeout for flaky testCACertLoader()

Bug: 37535489
Bug: 38045871
Test: runtest --path frameworks/base/packages/SystemUI/tests/src/com/android/systemui/statusbar/policy/SecurityControllerTest.java
Change-Id: I5778082973af7c6d4d719b83e334fec552b0a89e

Fix flaky SecurityControllerTest.testCaCertLoader

Fixes: 38108698
Test: runtest -c .statusbar.policy.SecurityControllerTest systemui
Change-Id: I6029a09984b72599622f0df57187a20aba4dab30

Disable flaky test

Test: treehugger
Bug: 38118260
Change-Id: I05c6504acee6a787e1cc5071bed0118388963212

(cherry picked from commit e375fc44)