Fixed Cts test failures of rounded corners

On devices with ignore_orientation_request set to true, the test
activity will be letterboxed in a landscape display which make the
activity not a fullscreen one.

We should set the ignore_orientation_request to false before testing
and restore it back when done with testing.

Bug: 205497113
Test: atest RoundedCornerTests
Change-Id: I70cb056cd654c3e47bf2cca9a447da93698998d9
Merged-In: I70cb056cd654c3e47bf2cca9a447da93698998d9