servo: Merge #18272 - Correct "is sorted" check in profile statistics (from mateon1:fix/profile-sorted-assert); r=emilio

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Correct the debug_assert check for whether or not statistics collected by the --profile flag are sorted.
I'm not sure how I could add a test for this change, and whether that is necessary.

I also wonder if it makes sense to replace the sort_by calls (currently using explicit comparisons) in this file with something like
```
data.sort_by(|a, b| a.partial_cmp(b).expect("no NaN in collected statistics"))
```

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #18270 (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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Source-Repo: https://github.com/servo/servo
Source-Revision: 2550b47decbc9876d96a459e399658ca54998bda

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : df9342b1e4cd360292fb3acb63192eeef209064c

servo/components/profile/time.rs

@@ -328,7 +328,7 @@ impl Profiler {
     /// Get tuple (mean, median, min, max) for profiler statistics.
     pub fn get_statistics(data: &[f64]) -> (f64, f64, f64, f64) {
         data.iter().fold(-f64::INFINITY, |a, &b| {
-            debug_assert!(a < b, "Data must be sorted");
+            debug_assert!(a <= b, "Data must be sorted");
             b
         });