Fix sandboxed process traversal in new OomAdjuster

When traversing the process graph, bindings to sandboxed processes by
system should be ignored and a virtual binding from the attributed
client should be used instead.

Also run assignCachedAdj on the whole lru list for partial updates. The algorithm inside currently relies on being aware of every process. See b/319163103.

Bug: 319696302
Test: atest SdkSandboxLifecycleHostTest:com.android.tests.sdksandbox.host.SdkSandboxLifecycleHostTest
Test: atest MockingOomAdjusterTests
Change-Id: Ie599ea62b9057e66a0b2e9b0b57c51c192abadfb