patch 8.2.4273: the EBCDIC support is outdated

Problem:    The EBCDIC support is outdated.
Solution:   Remove the EBCDIC support.
diff --git a/src/cindent.c b/src/cindent.c
index 747b509..ca21c12 100644
--- a/src/cindent.c
+++ b/src/cindent.c
@@ -3946,13 +3946,7 @@
 	    try_match_word = FALSE;
 
 	// does it look like a control character?
-	if (*look == '^'
-#ifdef EBCDIC
-		&& (Ctrl_chr(look[1]) != 0)
-#else
-		&& look[1] >= '?' && look[1] <= '_'
-#endif
-		)
+	if (*look == '^' && look[1] >= '?' && look[1] <= '_')
 	{
 	    if (try_match && keytyped == Ctrl_chr(look[1]))
 		return TRUE;