patch 8.2.1641: Vim9: cannot use 0 or 1 where a bool is expected

Problem:    Vim9: cannot use 0 or 1 where a bool is expected.
Solution:   Allow using 0 and 1 for a bool type. (closes #6903)
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 8d8111a..5712e38 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -45,6 +45,11 @@
   let bool2: bool = false
   assert_equal(v:false, bool2)
 
+  let bool3: bool = 0
+  assert_equal(0, bool3)
+  let bool4: bool = 1
+  assert_equal(1, bool4)
+
   CheckDefFailure(['let x:string'], 'E1069:')
   CheckDefFailure(['let x:string = "x"'], 'E1069:')
   CheckDefFailure(['let a:string = "x"'], 'E1069:')