patch 8.0.1794: duplicate term options after renaming

Problem:    Duplicate term options after renaming.
Solution:   Remove the old names 'termkey', 'termsize' and 'terminalscroll'.
diff --git a/src/testdir/gen_opt_test.vim b/src/testdir/gen_opt_test.vim
index 58db1f9..9d12ea0 100644
--- a/src/testdir/gen_opt_test.vim
+++ b/src/testdir/gen_opt_test.vim
@@ -131,7 +131,6 @@
       \ 'term': [[], []],
       \ 'termguicolors': [[], []],
       \ 'termencoding': [has('gui_gtk') ? [] : ['', 'utf-8'], ['xxx']],
-      \ 'termsize': [['', '24x80', '0x80', '32x0', '0x0'], ['xxx', '80', '8ax9', '24x80b']],
       \ 'termwinsize': [['', '24x80', '0x80', '32x0', '0x0'], ['xxx', '80', '8ax9', '24x80b']],
       \ 'toolbar': [['', 'icons', 'text'], ['xxx']],
       \ 'toolbariconsize': [['', 'tiny', 'huge'], ['xxx']],
diff --git a/src/testdir/screendump.vim b/src/testdir/screendump.vim
index 7065fa0..3c424a0 100644
--- a/src/testdir/screendump.vim
+++ b/src/testdir/screendump.vim
@@ -57,7 +57,7 @@
   " Add -v to have gvim run in the terminal (if possible)
   let cmd .= ' -v ' . a:arguments
   let buf = term_start(cmd, {'curwin': 1, 'term_rows': rows, 'term_cols': cols})
-  if &termsize == ''
+  if &termwinsize == ''
     call assert_equal([rows, cols], term_getsize(buf))
   else
     let rows = term_getsize(buf)[0]