patch 8.2.1079: Vim9: no line break allowed in a while loop

Problem:    Vim9: no line break allowed in a while loop.
Solution:   Update stored loop lines when finding line breaks.
diff --git a/src/evalvars.c b/src/evalvars.c
index 1d6172a..901d406 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -799,8 +799,11 @@
 		++emsg_skip;
 	    CLEAR_FIELD(evalarg);
 	    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
-	    evalarg.eval_cookie = eap->getline == getsourceline
-							  ? eap->cookie : NULL;
+	    if (getline_equal(eap->getline, eap->cookie, getsourceline))
+	    {
+		evalarg.eval_getline = eap->getline;
+		evalarg.eval_cookie = eap->cookie;
+	    }
 	    i = eval0(expr, &rettv, eap, &evalarg);
 	    if (eap->skip)
 		--emsg_skip;