Add full action printout to MotionEvent

Currently, not all actions are being printed in the input dump. This
results in hard-to-debug cases like the hover issue with multi-finger
operation before screen off.

Add printouts for all known action values, and add a number printout in
case an invalid value is received.

Bug: 169785626
Bug: 164506345
Test: adb shell dumpsys input
Change-Id: I885bf311eb28cca153887ebb382528927a736041
diff --git a/include/input/Input.h b/include/input/Input.h
index 7d81fed..ced1d0e 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -730,7 +730,7 @@
     static const char* getLabel(int32_t axis);
     static int32_t getAxisFromLabel(const char* label);
 
-    static const char* actionToString(int32_t action);
+    static std::string actionToString(int32_t action);
 
 protected:
     int32_t mAction;