Revert "test-driver: Set the date to the current time on boot"

This reverts commit 4e6eae45ee8c2357acf3dc7e3caba9d86c2edeac. It
breaks running the test driver interactively (in that it causes all
VMs to be started immediately, which is not always what you wnat).

nixos/lib/test-driver/test-driver.pl

@@ -52,7 +52,6 @@ sub createMachine {
     my ($args) = @_;
     my $vm = Machine->new({%{$args}, log => $log, redirectSerial => ($ENV{USE_SERIAL} // "0") ne "1"});
     $vms{$vm->name} = $vm;
-    $vm->execute("date -s @" . time);
     return $vm;
 }