With the backport of TDigest, the build started failing compiling with Java 20 with the following error:

```
> Task :libs:elasticsearch-tdigest:compileJava FAILED
../elasticsearch/libs/tdigest/src/main/java/org/elasticsearch/tdigest/SortingDigest.java:57: warning: [lossy-conversions] implicit cast from long to int in compound assignment is possibly lossy
            valuesToAddCount += other.size();
                                          ^
error: warnings found and -Werror specified
1 error
1 warning

```
Java 20 is more picky about lossy conversions,

libs/tdigest/src/test/java/org/elasticsearch/tdigest/ScaleFunctionTests.java
double q = i / n;
                        double k = f.k(q, compression, n);
                        assertTrue(String.format(Locale.ROOT, "monoticity %s(%.0f, %.0f) @ %.5f", f, compression, n, q), k > oldK);
                        oldK = k;
                        double qx = f.q(k, compression, n);
                        double kx = f.k(qx, compression, n);
                        assertEquals(String.format(Locale.ROOT, "Q: %s(%.0f, %.0f) @ %.5f", f, compression, n, q), q, qx, 1e-6);
                        double absError = abs(k - kx);
                        double relError = absError / max(0.01, max(abs(k), abs(kx)));
                        String info = String.format(
                            Locale.ROOT,
                            "K: %s(%.0f, %.0f) @ %.5f [%.5g, %.5g]",
                            f,
                            compression,
                            n,
                            q,
                            absError,
                            relError
                        );
                        assertEquals(info, 0, absError, tolerance);
                        assertEquals(info, 0, relError, tolerance);
                    }
                    assertTrue(f.k(0, compression, n) < f.k(epsilon, compression, n));
                    assertTrue(f.k(1, compression, n) > f.k(1 - epsilon, compression, n));
                }
            }
        }
    }
}