After the InputFlingerServiceTest is done, kill the service process
forked.

Kill the service process created during testing when the test is done.

Test: atest inputflinger_tests.
Change-Id: I5b5dc987da192e49d2524c2ff7779f3b54f65a9b
diff --git a/services/inputflinger/tests/InputFlingerService_test.cpp b/services/inputflinger/tests/InputFlingerService_test.cpp
index fd3f562..6d50519 100644
--- a/services/inputflinger/tests/InputFlingerService_test.cpp
+++ b/services/inputflinger/tests/InputFlingerService_test.cpp
@@ -402,7 +402,9 @@
     } else {
         android::ProcessState::self()->startThreadPool();
         ::testing::InitGoogleTest(&argc, argv);
-        return RUN_ALL_TESTS();
+        int result = RUN_ALL_TESTS();
+        kill(forkPid, SIGKILL);
+        return result;
     }
     return 0;
 }