patch 8.0.1011: terminal test fails with Athena and Motif

Problem:    Terminal test fails with Athena and Motif.
Solution:   Ignore the error for the input context. (Kazunobu Kuriyama)
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index d651d0b..ae6d195 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -429,6 +429,10 @@
   if !CanRunGui()
     return
   endif
+
+  " Ignore the "failed to create input context" error.
+  call test_ignore_error('E285:')
+
   gui -f
 
   call assert_equal(1, winnr('$'))