patch 8.0.0804: running tests fails when stdin is /dev/null

Problem:    Running tests fails when stdin is /dev/null. (James McCoy)
Solution:   Do not bail out from getting input if the --not-a-term argument
            was given. (closes #1460)
diff --git a/src/eval.c b/src/eval.c
index 4cb3289..c35def0 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -8070,8 +8070,9 @@
     rettv->vval.v_string = NULL;
 
 #ifdef NO_CONSOLE_INPUT
-    /* While starting up, there is no place to enter text. */
-    if (no_console_input())
+    /* While starting up, there is no place to enter text. When running tests
+     * with --not-a-term we assume feedkeys() will be used. */
+    if (no_console_input() && !is_not_a_term())
 	return;
 #endif