patch 8.2.0070: crash when using Python 3 with "debug" encoding

Problem:    Crash when using Python 3 with "debug" encoding. (Dominique Pelle)
Solution:   Use "euc-jp" whenever enc_dbcs is set.
diff --git a/src/testdir/test_python3.vim b/src/testdir/test_python3.vim
index 397299e..97f797e 100644
--- a/src/testdir/test_python3.vim
+++ b/src/testdir/test_python3.vim
@@ -172,5 +172,9 @@
   " this crashed Vim once
   set encoding=utf32
   py3 print('hello')
+  set encoding=debug
+  py3 print('hello')
+  set encoding=euc-tw
+  py3 print('hello')
   set encoding=utf8
 endfunc