RFR: 8297561: Redundant index check in String.offsetByCodePoints()

[Sergey Tsypanov]

On Thu, 24 Nov 2022 10:08:31 GMT, Sergey Tsypanov <stsypanov at openjdk.org> wrote:

> `String.offsetByCodePoints()` delegates to `Character.offsetByCodePoints()` which in turn specifies the same exception thrown under the same conditions and the implementation does exactly the same checks. This means we can remove the check from `String.offsetByCodePoints()` and rely on the one of `Character.offsetByCodePoints()`.

I've added a benchmark for the changes, on my machine it gives the following results:

baseline
Benchmark                                    Mode  Cnt  Score   Error  Units
StringOffsetByCodePoints.offsetByCodePoints  avgt   30  6.616 ± 0.040  ns/op

patch
Benchmark                                    Mode  Cnt  Score   Error  Units
StringOffsetByCodePoints.offsetByCodePoints  avgt   30  6.606 ± 0.008  ns/op

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PR: https://git.openjdk.org/jdk/pull/11350