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
Locale.ROOT,
                            "Different ways to compute scale function %s should agree, " + "compression=%.0f, n=%d, q=%.2f",
                            scale,
                            compression,
                            n,
                            q
                        );
                        assertEquals(remark, k1, k2, 1e-10);
                        assertTrue(String.format(Locale.ROOT, "Scale %s function should not decrease", scale), k1 >= last);
                        last = k1;
                    }
                    last = Double.NEGATIVE_INFINITY;
                    for (double k = scale.q(0, norm) - 2; k < scale.q(1, norm) + 2; k += 0.01) {
                        double q1 = scale.q(k, norm);
                        double q2 = scale.q(k, compression, n);
                        String remark = String.format(
                            Locale.ROOT,
                            "Different ways to compute inverse scale function %s should agree, " + "compression=%.0f, n=%d, q=%.2f",
                            scale,
                            compression,
                            n,
                            k
                        );
                        assertEquals(remark, q1, q2, 1e-10);
                        assertTrue(String.format(Locale.ROOT, "Inverse scale %s function should not decrease", scale), q1 >= last);
                        last = q1;
                    }
                }
            }
        }