patch 8.2.0527: Vim9: function types insufficiently tested

Problem:    Vim9: function types insufficiently tested.
Solution:   Add more tests.  Fix white space check.  Add "test_vim9" target.
diff --git a/src/version.c b/src/version.c
index bcf333b..f08ca11 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    527,
+/**/
     526,
 /**/
     525,