use interval for test

Author: pvdrz

tests/pass/shims/time-with-isolation.rs

@@ -1,5 +1,13 @@
 use std::time::{Duration, Instant};
 
+fn duration_sanity(diff: Duration) {
+    // The virtual clock is deterministic and I got 29us on a 64-bit Linux machine. However, this
+    // changes according to the platform so we use an interval to be safe. This should be updated
+    // if `NANOSECONDS_PER_BASIC_BLOCK` changes.
+    assert!(diff.as_micros() > 10);
+    assert!(diff.as_micros() < 40);
+}
+
 fn test_sleep() {
     let before = Instant::now();
     std::thread::sleep(Duration::from_millis(100));
@@ -20,9 +28,7 @@ fn main() {
     let diff = now2.duration_since(now1);
     assert_eq!(now1 + diff, now2);
     assert_eq!(now2 - diff, now1);
-    // The virtual clock is deterministic and I got 29us. This should be updated if
-    // `NANOSECONDS_PER_BASIC_BLOCK` changes.
-    assert_eq!(diff.as_micros(), 29);
+    duration_sanity(diff);
 
     test_sleep();
 }