Add toString and remove default case

For a future CL, we will need to print some bools. To facilitate that,
add a "toString" function.

Also, if we add a focus type, it would be good that the compiler
highlights cases where the new type isn't being handled in a switch
statement. Therefore, remove all default cases in switch statements
where feasible.

Because we are now adding an "unused" function that compiler complains
about, also convert DEBUG_TRANSPORT_ACTIONS into a constexpr bool.

Bug: none
Test: presubmit
Change-Id: Ie8472707f1699d2009232b9f36abae9a36a97f5f
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index c219941..aba5a30 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -2295,10 +2295,12 @@
                 reportTouchEventForStatistics(*motionEntry);
                 break;
             }
-
-            default:
-                ALOG_ASSERT(false);
+            case EventEntry::Type::CONFIGURATION_CHANGED:
+            case EventEntry::Type::DEVICE_RESET: {
+                LOG_ALWAYS_FATAL("Should never start dispatch cycles for %s events",
+                                 EventEntry::typeToString(eventEntry->type));
                 return;
+            }
         }
 
         // Check the result.