patch 8.2.1644: Vim9: cannot assign 1 and 0 to bool at script level

Problem:    Vim9: cannot assign 1 and 0 to bool at script level.
Solution:   Add the TTFLAG_BOOL_OK flag to the type. Fix name of test
            function.
diff --git a/src/version.c b/src/version.c
index 18d2b3e..1d1e00e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1644,
+/**/
     1643,
 /**/
     1642,