patch 8.1.1764: ":browse oldfiles" is not tested

Problem:    ":browse oldfiles" is not tested.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index da62479..6619c7b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1764,
+/**/
     1763,
 /**/
     1762,