Update CtsPreference2TestCases to prevent test app in landscape mode will fail

android.preference2.cts.PreferenceActivityFlowLandscapeTest#recreateLandscapeTest and
android.preference2.cts.PreferenceActivityLegacyFlowTest#legacyActivityRecreateTest failed.
Due to in landscape mode, navigation bar will show in right of the screen.
Original code will take wrong region to let test case failed.
The patch will adjust screen shot region according to current orientation.

Test:
1. make CtsPreference2TestCases –j4
2. Replace CtsPreference2TestCases.apk in android-cts/testcases/
3. ./android-cts/tools/cts-tradefed
4. run cts -m CtsPreference2TestCases

Bug: 123613807
Change-Id: Ibb4a0048c24131c7e7a395001dc97ea8ffdc4d35
Merged-In: Ibb4a0048c24131c7e7a395001dc97ea8ffdc4d35