patch 8.0.0478: tests use assert_true(0) and assert_false(1) to report errors

Problem:    Tests use assert_true(0) and assert_false(1) to report errors.
Solution:   Use assert_report().
diff --git a/src/testdir/test_menu.vim b/src/testdir/test_menu.vim
index 8acc844..055d944 100644
--- a/src/testdir/test_menu.vim
+++ b/src/testdir/test_menu.vim
@@ -8,7 +8,7 @@
   try
     source $VIMRUNTIME/menu.vim
   catch
-    call assert_false(1, 'error while loading menus: ' . v:exception)
+    call assert_report('error while loading menus: ' . v:exception)
   endtry
   call assert_match('browse confirm w', execute(':menu File.Save'))
   source $VIMRUNTIME/delmenu.vim