patch 8.2.3815: Vim9: cannot have a multi-line dict inside a block

Problem:    Vim9: cannot have a multi-line dict inside a block.
Solution:   Do not split the command at a line break, handle NL characters
            as white space.

src/eval.c

@@ -2150,7 +2150,7 @@ eval_next_line(evalarg_T *evalarg)
 skipwhite_and_linebreak(char_u *arg, evalarg_T *evalarg)
 {
     int	    getnext;
-    char_u  *p = skipwhite(arg);
+    char_u  *p = skipwhite_and_nl(arg);
 
     if (evalarg == NULL)
 	return skipwhite(arg);