patch 8.2.0300: Vim9: expression test fails without channel support

Problem:    Vim9: expression test fails without channel support.
Solution:   Add has('channel') check.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index a5b6e44..fb7d39f 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -773,8 +773,10 @@
   assert_equal(true, !{})
   assert_equal(false, !{'yes': 'no'})
 
-  assert_equal(true, !test_null_job())
-  assert_equal(true, !test_null_channel())
+  if has('channel')
+    assert_equal(true, !test_null_job())
+    assert_equal(true, !test_null_channel())
+  endif
 
   assert_equal(true, !test_null_blob())
   assert_equal(true, !0z)
diff --git a/src/version.c b/src/version.c
index 95a098b..16bf1e1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    300,
+/**/
     299,
 /**/
     298,