patch 8.2.1630: terminal test fails

Problem:    Terminal test fails.
Solution:   Correct argument to term_start().  Correct error number.
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index fbb725c..207ef9a 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -912,7 +912,7 @@
   endif
 
   enew
-  let buf = term_start(cmd, {'curwin': bufnr('')})
+  let buf = term_start(cmd, {'curwin': 1})
   let g:job = term_getjob(buf)
   call WaitFor({-> term_getline(buf, 1) !=# ''}, 1000)