RFR: 8316704: Regex-free parsing of Formatter and FormatProcessor specifiers

[温绍锦]

@cl4es made performance optimizations for the simple specifiers of String.format in PR https://github.com/openjdk/jdk/pull/2830. Based on the same idea, I continued to make improvements. I made patterns like %2d %02d also be optimized.

The following are the test results based on MacBookPro M1 Pro: 


-Benchmark                          Mode  Cnt     Score     Error  Units
-StringFormat.complexFormat         avgt   15  1862.233 ? 217.479  ns/op
-StringFormat.int02Format           avgt   15   312.491 ?  26.021  ns/op
-StringFormat.intFormat             avgt   15    84.432 ?   4.145  ns/op
-StringFormat.longFormat            avgt   15    87.330 ?   6.111  ns/op
-StringFormat.stringFormat          avgt   15    63.985 ?  11.366  ns/op
-StringFormat.stringIntFormat       avgt   15    87.422 ?   0.147  ns/op
-StringFormat.widthStringFormat     avgt   15   250.740 ?  32.639  ns/op
-StringFormat.widthStringIntFormat  avgt   15   312.474 ?  16.309  ns/op

+Benchmark                          Mode  Cnt    Score    Error  Units
+StringFormat.complexFormat         avgt   15  740.626 ? 66.671  ns/op (+151.45)
+StringFormat.int02Format           avgt   15  131.049 ?  0.432  ns/op (+138.46)
+StringFormat.intFormat             avgt   15   67.229 ?  4.155  ns/op (+25.59)
+StringFormat.longFormat            avgt   15   66.444 ?  0.614  ns/op (+31.44)
+StringFormat.stringFormat          avgt   15   62.619 ?  4.652  ns/op (+2.19)
+StringFormat.stringIntFormat       avgt   15   89.606 ? 13.966  ns/op (-2.44)
+StringFormat.widthStringFormat     avgt   15   52.462 ? 15.649  ns/op (+377.95)
+StringFormat.widthStringIntFormat  avgt   15  101.814 ?  3.147  ns/op (+206.91)

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Commit messages:
 - shared between Formatter and FormatProcessor
 - refactor & bug fix
 - refactor
 - bug fix for '%T' not throw error
 - bug fix
 - drop the regex code entirely and write a custom parser
 - fix specifiers duplicate flags not throw error
 - fix specifiers support '%<s'
 - parse fast-path support more specifiers
 - remove unused comment
 - ... and 6 more: https://git.openjdk.org/jdk/compare/c92bdb0e...59c2983b

Changes: https://git.openjdk.org/jdk/pull/15776/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15776&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316704
  Stats: 307 lines in 3 files changed: 272 ins; 14 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/15776.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15776/head:pull/15776

PR: https://git.openjdk.org/jdk/pull/15776