patch 8.2.1724: Vim9: assignment tests spread out

Problem:    Vim9: assignment tests spread out.
Solution:   Create new test file for assignment tests.
diff --git a/src/version.c b/src/version.c
index b6cb477..5f1767b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1724,
+/**/
     1723,
 /**/
     1722,