Extract JoystickInputMapperTest to its own file

Bug: 245989146
Test: atest frameworks/native/services/inputflinger/tests/JoystickInputMapper_test.cpp
Flag: TEST_ONLY
Change-Id: Ie11146c27d3fbbfe90c8a119f15fb0fdf3dfd3d5
diff --git a/services/inputflinger/tests/Android.bp b/services/inputflinger/tests/Android.bp
index ab50646..95283ba 100644
--- a/services/inputflinger/tests/Android.bp
+++ b/services/inputflinger/tests/Android.bp
@@ -70,6 +70,7 @@
         "InputTraceSession.cpp",
         "InputTracingTest.cpp",
         "InstrumentedInputReader.cpp",
+        "JoystickInputMapper_test.cpp",
         "LatencyTracker_test.cpp",
         "MultiTouchMotionAccumulator_test.cpp",
         "NotifyArgs_test.cpp",