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/vim9compile.c b/src/vim9compile.c
index 3eae641..80f918d 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -7048,7 +7048,7 @@
 	// Push v:exception, push {expr} and MATCH
 	generate_instr_type(cctx, ISN_PUSHEXC, &t_string);
 
-	end = skip_regexp_ex(p + 1, *p, TRUE, &tofree, &dropped);
+	end = skip_regexp_ex(p + 1, *p, TRUE, &tofree, &dropped, NULL);
 	if (*end != *p)
 	{
 	    semsg(_(e_separator_mismatch_str), p);
@@ -7372,7 +7372,7 @@
     {
 	int delim = *eap->arg;
 
-	p = skip_regexp_ex(eap->arg + 1, delim, TRUE, NULL, NULL);
+	p = skip_regexp_ex(eap->arg + 1, delim, TRUE, NULL, NULL, NULL);
 	if (*p == delim)
 	{
 	    eap->arg = p + 1;