Fixing AccessibilityTakeScreenshotTest failure at low ram devices

The activity could not be launched at non-default display if this
device is a low ram device. So adding the checking condition of
supporting multi-display at these test cases skips these tests
that need to launch activity on second display at a low ram device.

BUG: 170273534
Test: run cts -m CtsAccessibilityServiceTestCases
Change-Id: I08b4bae91ae7950bc1ba72f130e9efe8b2a9b47f
1 file changed