Remove pointer warp from test boilerplate

Remove the line to warp the pointer to (0, 0) in `new-test` helper
script, which is used to create new tests.

Since 4.6-g0634766, testcases may assume at the start of the test that
the pointer begins at position (0, 0).

testcases/new-test

@@ -83,10 +83,6 @@ if ($multi_monitor) {
     print $fh <<'EOF';
 use i3test i3_autostart => 0;
 
-# Ensure the pointer is at (0, 0) so that we really start on the first
-# (the left) workspace.
-$x->root->warp_pointer(0, 0);
-
 my $config = <<EOT;
 # i3 config file (v4)
 font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1