patch 8.2.2295: incsearch does not detect empty pattern properly

Problem:    Incsearch does not detect empty pattern properly.
Solution:   Return magic state when skipping over a pattern. (Christian
            Brabandt, closes #7612, closes #6420)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 734949c..c61810f 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -3672,7 +3672,7 @@
 	    delimiter = *cmd++;		    // remember delimiter character
 	    pat = cmd;			    // remember start of search pat
 	    cmd = skip_regexp_ex(cmd, delimiter, magic_isset(),
-							      &eap->arg, NULL);
+							&eap->arg, NULL, NULL);
 	    if (cmd[0] == delimiter)	    // end delimiter found
 		*cmd++ = NUL;		    // replace it with a NUL
 	}
@@ -4856,7 +4856,7 @@
 	if (delim)
 	    ++cmd;		// skip delimiter if there is one
 	pat = cmd;		// remember start of pattern
-	cmd = skip_regexp_ex(cmd, delim, magic_isset(), &eap->arg, NULL);
+	cmd = skip_regexp_ex(cmd, delim, magic_isset(), &eap->arg, NULL, NULL);
 	if (cmd[0] == delim)		    // end delimiter found
 	    *cmd++ = NUL;		    // replace it with a NUL
     }