Do not check isInMultiWindowMode in PIP mode tests.

The assertion does not necessary hold. On an environment that launches
activities in multi-window mode by default, the failure in
enterPictureInPictureMode() just keeps the previous multi-window state.

Bug: 33642679
Test: run the tests on ARC.
Change-Id: I2b26de0dcedda675ae757d2dc8939ae7befb8149
diff --git a/tests/app/src/android/app/cts/PipNotResizeableActivityTest.java b/tests/app/src/android/app/cts/PipNotResizeableActivityTest.java
index 7189dc1..e2a4aff 100644
--- a/tests/app/src/android/app/cts/PipNotResizeableActivityTest.java
+++ b/tests/app/src/android/app/cts/PipNotResizeableActivityTest.java
@@ -51,7 +51,6 @@
                         pipSupportDisabled = true;
                     }
                     assertTrue(pipSupportDisabled);
-                    assertFalse(mActivity.isInMultiWindowMode());
                     assertFalse(mActivity.isInPictureInPictureMode());
                 }
             });
diff --git a/tests/app/src/android/app/cts/PipNotSupportedActivityTest.java b/tests/app/src/android/app/cts/PipNotSupportedActivityTest.java
index e8d13dc..d33ff4d 100644
--- a/tests/app/src/android/app/cts/PipNotSupportedActivityTest.java
+++ b/tests/app/src/android/app/cts/PipNotSupportedActivityTest.java
@@ -51,7 +51,6 @@
                     pipSupportDisabled = true;
                 }
                 assertTrue(pipSupportDisabled);
-                assertFalse(mActivity.isInMultiWindowMode());
                 assertFalse(mActivity.isInPictureInPictureMode());
             }
         });