ISSUE-2492: Bug in ArrayGroupSort.java (in line 88, keySize shall be groupSize)

[sijie]

Original Issue: apache/bookkeeper#2492

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BUG REPORT

Describe the bug

I am browsing the codes and just suspecting there is a bug in ArrayGroupSort.java(https://github.com/apache/bookkeeper/blob/master/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/ArrayGroupSort.java#L88)

in line 88, keySize shall be groupSize instead?

    private boolean isLess(long[] array, int idx1, int idx2) {
        for (int i = 0; i < keySize; i++) {     // bug? keySize shall be groupSize instead?
            long k1 = array[idx1 + i];
            long k2 = array[idx2 + i];
            if (k1 < k2) {
                return true;
            } else if (k1 > k2) {
                return false;
            }
        }

        return false;
    }

To Reproduce

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Expected behavior

A clear and concise description of what you expected to happen.

Screenshots

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Additional context

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