Use getRealMetrics for screen configuration tests

The tests in ConfigurationTest as part of test module CtsDpiTestCases
fail on small screen devices due to usage of Display#getMetrics()
instead of Display#getRealMetrics().

As per documentation getRealMetrics() "gets display metrics based on the
real size of this display" while getMetrics() may "not necessarily
represent the actual raw size (native resolution) of the display".

Test: run cts -m CtsDpiTestCases \
        -t android.dpi.cts.ConfigurationTest#testScreenConfiguration
Bug: 147247314
Change-Id: Ifc5a42f1b9f6b4ee727b30aa6dae910765179909
Signed-off-by: Daniel Kutik <daniel.kutik@lavawerk.com>
diff --git a/tests/tests/dpi/src/android/dpi/cts/ConfigurationTest.java b/tests/tests/dpi/src/android/dpi/cts/ConfigurationTest.java
index 8fdc701..e3b198b 100644
--- a/tests/tests/dpi/src/android/dpi/cts/ConfigurationTest.java
+++ b/tests/tests/dpi/src/android/dpi/cts/ConfigurationTest.java
@@ -44,7 +44,7 @@
                 (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
         Display display = windowManager.getDefaultDisplay();
         mMetrics = new DisplayMetrics();
-        display.getMetrics(mMetrics);
+        display.getRealMetrics(mMetrics);
     }
 
     @Presubmit