patch 8.2.3216: Vim9: crash when using variable in a loop at script level

Problem:    Vim9: crash when using variable in a loop at script level.
Solution:   Do not clear the variable if a function was defined.
            Do not create a new entry in sn_var_vals every time.
            (closes #8628)
diff --git a/src/evalvars.c b/src/evalvars.c
index 1f781da..534163c 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -880,13 +880,7 @@
 
 	    if (eap->skip)
 		++emsg_skip;
-	    CLEAR_FIELD(evalarg);
-	    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
-	    if (getline_equal(eap->getline, eap->cookie, getsourceline))
-	    {
-		evalarg.eval_getline = eap->getline;
-		evalarg.eval_cookie = eap->cookie;
-	    }
+	    fill_evalarg_from_eap(&evalarg, eap, eap->skip);
 	    expr = skipwhite_and_linebreak(expr, &evalarg);
 	    cur_lnum = SOURCING_LNUM;
 	    i = eval0(expr, &rettv, eap, &evalarg);