Inside Solution, implement the harness and use it:
1. static long sumTo(int n) — plain loop sum 1..n, return the sum (the workload).
2. static long measureSumMicros(int n, int rounds) — warm up 2_000 untimed runs,
then time rounds runs of sumTo(n) in MICROS; return the MEDIAN. Every run's result
must be verified against n*(n+1)/2 (consume it).
3. static boolean fasterWithinEpsilon(long aMicros, long bMicros, double epsFrac) —
true iff a < b AND the gap (b - a) exceeds epsFrac * b (b is the slower
baseline; a only wins beyond the epsilon).
4. static String claim(long aMicros, long bMicros) — return "faster" if
fasterWithinEpsilon(a, b, 0.10), "slower" if fasterWithinEpsilon(b, a, 0.10),
else "no measured difference".
Difficulty: advanced