Correctly handle TargetAccessibilityFocus flag

In current implementation of GroupView, TargetAccessibilityFocus flag is
not reflected while searching the node to dispatch the touch event.

History:
The logic to search the accessibility focused node was removed in CL [1].
CL [1] was reverted in [2], but the logic is not correctly restored.

[1] I84bba65ac16e27e9c564b23a0c27d48245eef447
[2] I427b98c71ce8a2ac5b9285b2f34c1864f48c4a32

Bug: 159168795, 182434603
Test: atest TouchExplorerTest
Change-Id: I911547dd506511dd830c8b051af3264523b75df2