patch 8.2.1555: not all tests are executed on Github Actions

Problem:    Not all tests are executed on Github Actions.
Solution:   Copy "src" to "src2" earlier. Recognize "src2" in a couple more
            places.  Add two tests to the list of flaky tests. (Ken Takata,
            closes #6798)
diff --git a/src/testdir/test_python2.vim b/src/testdir/test_python2.vim
index 8fa7340..fd8fe70 100644
--- a/src/testdir/test_python2.vim
+++ b/src/testdir/test_python2.vim
@@ -2412,7 +2412,7 @@
     cb.append(vim.eval('@%'))
     os.chdir('..')
     path = fnamemodify('.', ':p:h:t')
-    if path != 'src':
+    if path != 'src' and path != 'src2':
       # Running tests from a shadow directory, so move up another level
       # This will result in @% looking like shadow/testdir/Xfile, hence the
       # extra fnamemodify
@@ -2422,7 +2422,8 @@
       os.chdir(path)
       del path
     else:
-      cb.append(fnamemodify('.', ':p:h:t'))
+      # Also accept running from src2/testdir/ for MS-Windows CI.
+      cb.append(fnamemodify('.', ':p:h:t').replace('src2', 'src'))
       cb.append(vim.eval('@%').replace(os.path.sep, '/'))
     os.chdir('testdir')
     cb.append(fnamemodify('.', ':p:h:t'))