RFR: 8310929: Optimization for Integer.toString

[温绍锦]

Speed up Integer.toString with a precomputed cache array of length 1000, use division by 1000, so that each iteration can calculate three digits.  

this optimization can also be used in StringBuilder#appent(int) and Long#toString.

# Benchmark Result


make test TEST="micro:java.lang.Integers.toString*"


## [aliyun_ecs_c8i.xlarge](https://help.aliyun.com/document_detail/25378.html#c8i)
* cpu : intel xeon sapphire rapids (x64)
``` diff
-Benchmark               (size)  Mode  Cnt  Score   Error  Units (baseline)
-Integers.toStringBig       500  avgt   15  6.811 ± 0.016  us/op
-Integers.toStringSmall     500  avgt   15  4.794 ± 0.011  us/op
-Integers.toStringTiny      500  avgt   15  3.752 ± 0.065  us/op

+Benchmark               (size)  Mode  Cnt  Score   Error  Units (PR)
+Integers.toStringBig       500  avgt   15  5.164 ± 0.052  us/op +31.89%
+Integers.toStringSmall     500  avgt   15  3.844 ± 0.025  us/op +24.71%
+Integers.toStringTiny      500  avgt   15  3.453 ± 0.027  us/op +8.65%


### [aliyun_ecs_c8a.xlarge](https://help.aliyun.com/document_detail/25378.html#c8a)
* cpu : amd epc genoa (x64)
``` diff
-Benchmark               (size)  Mode  Cnt  Score   Error  Units (baseline)
-Integers.toStringBig       500  avgt   15  6.762 ± 0.018  us/op
-Integers.toStringSmall     500  avgt   15  4.481 ± 0.004  us/op
-Integers.toStringTiny      500  avgt   15  2.761 ± 0.012  us/op

+Benchmark               (size)  Mode  Cnt  Score   Error  Units (PR)
+Integers.toStringBig       500  avgt   15  5.063 ± 0.175  us/op +33.55%
+Integers.toStringSmall     500  avgt   15  3.498 ± 0.123  us/op +28.10%
+Integers.toStringTiny      500  avgt   15  2.743 ± 0.147  us/op +0.65%


## [aliyun_ecs_c8y.xlarge](https://help.aliyun.com/document_detail/25378.html#c8y)
* cpu : aliyun yitian 710 (aarch64)
``` diff
-Benchmark               (size)  Mode  Cnt   Score   Error  Units (baseline)
-Integers.toStringBig       500  avgt   15  12.081 ± 0.377  us/op
-Integers.toStringSmall     500  avgt   15   7.119 ± 0.177  us/op
-Integers.toStringTiny      500  avgt   15   6.323 ± 0.239  us/op

+Benchmark               (size)  Mode  Cnt  Score   Error  Units (PR)
+Integers.toStringBig       500  avgt   15  8.157 ± 0.274  us/op +48.10%
+Integers.toStringSmall     500  avgt   15  7.207 ± 0.330  us/op -1.22%
+Integers.toStringTiny      500  avgt   15  6.912 ± 0.199  us/op -8.52%

-------------

Commit messages:
 - 8310929: Optimization for Integer.toString

Changes: https://git.openjdk.org/jdk/pull/14699/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14699&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310929
  Stats: 159 lines in 1 file changed: 153 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14699.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14699/head:pull/14699

PR: https://git.openjdk.org/jdk/pull/14699