<i18n dev> RFR: 8330802: Desugar switch in Locale::createLocale [v2]

[Claes Redestad]

> This switch expression in `Locale::createLocale` is causing a somewhat large startup regression on my local system. Desugaring to if statements seem like the right thing to do while we investigate ways to further reduce overheads in `SwitchBootstraps`.
> 
> These numbers are against a baseline which include #18865 and #18845, which already improved the situation:
> 
> 
> Name             Cnt          Base         Error           Test         Error         Unit  Change
> Perfstartup-Noop  20        40,500 ±       1,942         31,000 ±       2,673        ms/op   1,31x (p = 0,000*)
>   :.cycles           143254849,000 ± 3398321,355  102205427,650 ± 2192784,853       cycles   0,71x (p = 0,000*)
>   :.instructions     307138448,850 ± 2095834,550  219415574,800 ±  376992,067 instructions   0,71x (p = 0,000*)
>   :.taskclock               39,500 ±       1,942         22,500 ±       3,858           ms   0,57x (p = 0,000*)
>   * = significant
> 
> 
> Comparing to a baseline without those recent improvements the overhead was almost the double: 
> 
> Name             Cnt          Base         Error           Test         Error         Unit  Change
> Perfstartup-Noop  20        50,000 ±       0,000         31,000 ±       2,673        ms/op   1,61x (p = 0,000*)
>   :.cycles           187047932,000 ± 3330400,381  102205427,650 ± 2192784,853       cycles   0,55x (p = 0,000*)
>   :.instructions     408219060,350 ± 4031173,140  219415574,800 ±  376992,067 instructions   0,54x (p = 0,000*)
>   :.taskclock               53,500 ±       4,249         22,500 ±       3,858           ms   0,42x (p = 0,000*)
>   * = significant

Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:

  Remove InternalError in favor of CCE

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18882/files
  - new: https://git.openjdk.org/jdk/pull/18882/files/c4f5ee7c..0afa47ba

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18882&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18882&range=00-01

  Stats: 6 lines in 1 file changed: 2 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18882.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18882/head:pull/18882

PR: https://git.openjdk.org/jdk/pull/18882