patch 8.2.2872: Python tests fail without the channel feature

Problem:    Python tests fail without the channel feature.
Solution:   Add a feature check. (Dominique Pellé, closes #8226)
diff --git a/src/testdir/test_python2.vim b/src/testdir/test_python2.vim
index cf35a50..84c9173 100644
--- a/src/testdir/test_python2.vim
+++ b/src/testdir/test_python2.vim
@@ -814,8 +814,12 @@
   call assert_equal(v:none, pyeval("vim.bindeval('v:none')"))
 
   " channel/job
-  call assert_equal(v:none, pyeval("vim.bindeval('test_null_channel()')"))
-  call assert_equal(v:none, pyeval("vim.bindeval('test_null_job()')"))
+  if has('channel')
+    call assert_equal(v:none, pyeval("vim.bindeval('test_null_channel()')"))
+  endif
+  if has('job')
+    call assert_equal(v:none, pyeval("vim.bindeval('test_null_job()')"))
+  endif
 endfunc
 
 " threading
diff --git a/src/testdir/test_python3.vim b/src/testdir/test_python3.vim
index 58b6427..1e9ef82 100644
--- a/src/testdir/test_python3.vim
+++ b/src/testdir/test_python3.vim
@@ -1007,8 +1007,12 @@
   call assert_equal(v:none, py3eval("vim.bindeval('v:none')"))
 
   " channel/job
-  call assert_equal(v:none, py3eval("vim.bindeval('test_null_channel()')"))
-  call assert_equal(v:none, py3eval("vim.bindeval('test_null_job()')"))
+  if has('channel')
+    call assert_equal(v:none, py3eval("vim.bindeval('test_null_channel()')"))
+  endif
+  if has('job')
+    call assert_equal(v:none, py3eval("vim.bindeval('test_null_job()')"))
+  endif
 endfunc
 
 " threading