patch 9.0.1777: patch 9.0.1771 causes problems

Problem:  patch 9.0.1771 causes problems
Solution: revert it

Revert "patch 9.0.1771: regex: combining chars in collections not handled"
This reverts commit ca22fc36a4e8a315f199893ee8ff6253573f5fbe.

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/regexp_bt.c b/src/regexp_bt.c
index 198946e..522cf37 100644
--- a/src/regexp_bt.c
+++ b/src/regexp_bt.c
@@ -3743,38 +3743,13 @@
 
 	  case ANYOF:
 	  case ANYBUT:
-	    {
-		char_u  *q = OPERAND(scan);
-
-		if (c == NUL)
-		    status = RA_NOMATCH;
-		else if ((cstrchr(q, c) == NULL) == (op == ANYOF))
-		    status = RA_NOMATCH;
-		else
-		{
-		    // Check following combining characters
-		    int	len = 0;
-		    int i;
-
-		    if (enc_utf8)
-			len = utfc_ptr2len(q) - utf_ptr2len(q);
-
-		    MB_CPTR_ADV(rex.input);
-		    MB_CPTR_ADV(q);
-
-		    if (!enc_utf8 || len == 0)
-			break;
-
-		    for (i = 0; i < len; ++i)
-			if (q[i] != rex.input[i])
-			{
-			    status = RA_NOMATCH;
-			    break;
-			}
-		    rex.input += len;
-		}
-		break;
-	    }
+	    if (c == NUL)
+		status = RA_NOMATCH;
+	    else if ((cstrchr(OPERAND(scan), c) == NULL) == (op == ANYOF))
+		status = RA_NOMATCH;
+	    else
+		ADVANCE_REGINPUT();
+	    break;
 
 	  case MULTIBYTECODE:
 	    if (has_mbyte)