patch 8.2.2444: Vim9: compile error with combination of operator and list

Problem:    Vim9: compile error with combination of operator and list.
Solution:   Generate constants before parsing a list or dict. (closes #7757)
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 5b9f7f5..a9edc80 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -4121,13 +4121,17 @@
 	/*
 	 * List: [expr, expr]
 	 */
-	case '[':   ret = compile_list(arg, cctx, ppconst);
+	case '[':   if (generate_ppconst(cctx, ppconst) == FAIL)
+			return FAIL;
+		    ret = compile_list(arg, cctx, ppconst);
 		    break;
 
 	/*
 	 * Dictionary: {'key': val, 'key': val}
 	 */
-	case '{':   ret = compile_dict(arg, cctx, ppconst);
+	case '{':   if (generate_ppconst(cctx, ppconst) == FAIL)
+			return FAIL;
+		    ret = compile_dict(arg, cctx, ppconst);
 		    break;
 
 	/*