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

This reverts commit 4e6eae45ee. 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;
 }