Wait for each orientation request in ApplicationTest

Orientation change may restart an acivity, so waitForIdleSync
can make the test flaky.

However, we can't use OrientationTestUtils.Observer becasue
global configuration won't happen if the activity is in multi
window mode.

To make the test more reliable and still passes on both
multi-window mode and non multi-window mode, we need
to wait for each orientation request.

Bug: 115551150
Test: ApplicationTest pass
Change-Id: I16398015104ddb068a2a7f8275ea2f1dbaa0b703