patch 9.0.0823: mouse drag test fails

Problem:    Mouse drag test fails.
Solution:   Only reset the mouse click flag when actually switching to another
            tab page.  Disable test that keeps failing.
diff --git a/src/version.c b/src/version.c
index 387c811..16054b0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    823,
+/**/
     822,
 /**/
     821,