Add tests for previous fixes

Add tests for the fixes made in commits
76cb1144ef,
a465b7f58f,
0f522fb32a,
82969f045c and
673befd2d7.

tests/tests2/62_enumerator_redefinition.c

@@ -0,0 +1,4 @@
+enum color {RED, GREEN, BLUE};
+enum rgb {RED, G, B};
+
+enum color c = RED;