Add a value to FLOAT_TRAIT enum to enforce use of default case in switches

Revert the previous commit. Add tests for extended enum cases.
 Fix crash due to accessing 'trait_names' array out of bounds.
 Adding an extra invalid value to the end of an enum causes '-Wswitch' flag
  to warn unless there is a switch default case - also enabled by '-Wall'.

src/unity_internals.h

@@ -396,7 +396,8 @@ typedef enum _UNITY_FLOAT_TRAIT_T
     UNITY_FLOAT_IS_NOT_NAN,
     UNITY_FLOAT_IS_NAN,
     UNITY_FLOAT_IS_NOT_DET,
-    UNITY_FLOAT_IS_DET
+    UNITY_FLOAT_IS_DET,
+    UNITY_FLOAT_INVALID_TRAIT
 } UNITY_FLOAT_TRAIT_T;
 #endif