`handling_channel_announcements` is flaky on windows

[TheBlueMatt]

Don't think I've seen this one yet:

 ---- routing::gossip::tests::handling_channel_announcements stdout ----
thread 'routing::gossip::tests::handling_channel_announcements' panicked at lightning\src\routing\gossip.rs:2548:22:
explicit panic
stack backtrace:
   0: std::panicking::begin_panic_handler
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library\std\src\panicking.rs:645
   1: core::panicking::panic_fmt
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library\core\src\panicking.rs:72
   2: core::panicking::panic_display<ref$<str$> >
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library\core\src\panicking.rs:197
   3: core::panicking::panic_explicit
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library\core\src\panicking.rs:180
   4: lightning::routing::gossip::tests::handling_channel_announcements::panic_cold_explicit
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6\library\core\src\panic.rs:87
   5: lightning::routing::gossip::tests::handling_channel_announcements
             at .\src\routing\gossip.rs:2548
   6: lightning::routing::gossip::tests::handling_channel_announcements::closure$0
             at .\src\routing\gossip.rs:2453
   7: core::ops::function::FnOnce::call_once<lightning::routing::gossip::tests::handling_channel_announcements::closure_env$0,tuple$<> >
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6\library\core\src\ops\function.rs:250
   8: core::ops::function::FnOnce::call_once
             at /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library\core\src\ops\function.rs:250
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

failures:
    routing::gossip::tests::handling_channel_announcements

[TheBlueMatt]

Oh, I think this was just cause CI was slow and time advanced enough during the test that we failed. Should be an easy fix if someone digs into it.