Spurious test failure in metadata_access_times

[RalfJung]

On aarch64-gnu-llvm-20-1 (here):

	---- fs::tests::metadata_access_times stdout ----

thread 'fs::tests::metadata_access_times' (250955) panicked at library/std/src/fs/tests.rs:1737:33:
assertion failed: t1 <= t2
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: core::ops::function::FnOnce::call_once
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
---- fs::tests::metadata_access_times stdout end ----

failures:
    fs::tests::metadata_access_times

This test does not seem to have changed recently, so this might be pretty rare. I guess it can happen when the system clock moves backwards?

[mattiapitossi]

@rustbot claim