<i18n dev> RFR: 8335252: Reduce size of j.u.Formatter.Conversion#isValid [v4]

[Shaojin Wen]

> Currently, the java.util.Formatter$Conversion::isValid method is implemented based on switch, which cannot be inlined because codeSize > 325. This problem can be avoided by implementing it with ImmutableBitSetPredicate.
> 
> use `-XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining` to see the master branch:
> 
> @ 109   java.util.Formatter$Conversion::isValid (358 bytes)   failed to inline: hot method too big
> 
> 
> current version
> 
> @ 109   java.util.Formatter$Conversion::isValid (10 bytes)   inline (hot)
>   @ 4   jdk.internal.util.ImmutableBitSetPredicate$SmallImmutableBitSetPredicate::test (50 bytes)   inline (hot)

Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:

  fix comment

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19926/files
  - new: https://git.openjdk.org/jdk/pull/19926/files/192aa465..5707dc67

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19926&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19926&range=02-03

  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/19926.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19926/head:pull/19926

PR: https://git.openjdk.org/jdk/pull/19926