Reduce method invocation when checking orientation

This also prevents rotationForActivityInDifferentOrientation from
returning unexpected rotation if AR#getOverrideOrientation returns
a different orientation than getRequestedOrientation.

Bug: 159103089
Flag: EXEMPT simple refactor
Test: atest DisplayContentTests
Change-Id: I64a3f92ff6d83a0797b95d5656e15ad5f603959a