Add an end-to-end regression test for Bug 152698568

This CL introduces an end-to-end regression test for Bug 152698568,
which was already fixed [1].

 [1]: Ic113f564e964ebb0ab3375cf1df78b3f912169da
      fdec32c83f7dd828bb962833f220bbf5bc5f7d71

Fix: 153580952
Test: atest CtsInputMethodTestCases:FocusHandlingTest
Change-Id: I962bf0a6b65dc19c894a0088e714644adfc914c8
1 file changed