RFR: JDK-8284726: Print active locale settings in hs_err reports and in VM.info

[Thomas Stuefe]

To analyze locale problems in native code - e.g. stemming from third-party code calling `setlocale(3)` - it would be useful to print the active locale settings in hs-err reports and in VM.info.

Patch notes: 
- Posix is fuzzy about the exact role of LC_ALL. It defines LC_ALL as a way to set all locales in one go, but the implementation could still keep the individual categories separately and just let LC_ALL override the individual settings. Therefore I opted to print both, even though on glibc the information seems redundant.
- Since this is Posix specific, callers require #ifndef _WIN32 in shared files. That's not nice, but the alternative would be an empty stub implementation for windows, which I find also unappealing.

Example output, Ubuntu 20.04:

Java started with LC_ALL=C:

thomas at starfish $ jjjcmd Simple VM.info | ack LC_
LC_ALL=C
LC_ALL=C
LC_COLLATE=C
LC_CTYPE=C
LC_MESSAGES=C
LC_MONETARY=C
LC_NUMERIC=C
LC_TIME=C


Java started with my default system settings:

thomas at starfish:/shared/projects/openjdk/jdk-jdk/source/src/hotspot$ jjjcmd Simple VM.info | ack LC_
LC_ALL=LC_CTYPE=C;LC_NUMERIC=en_DK.UTF-8;LC_TIME=en_DK.UTF-8;LC_COLLATE=C;LC_MONETARY=en_DK.UTF-8;LC_MESSAGES=C;LC_PAPER=en_DK.UTF-8;LC_NAME=en_DK.UTF-8;LC_ADDRESS=en_DK.UTF-8;LC_TELEPHONE=en_DK.UTF-8;LC_MEASUREMENT=en_DK.UTF-8;LC_IDENTIFICATION=en_DK.UTF-8
LC_COLLATE=C
LC_CTYPE=C
LC_MESSAGES=C
LC_MONETARY=en_DK.UTF-8
LC_NUMERIC=en_DK.UTF-8
LC_TIME=en_DK.UTF-8

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Commit messages:
 - print posix locale categories

Changes: https://git.openjdk.java.net/jdk/pull/8194/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8194&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284726
  Stats: 44 lines in 3 files changed: 44 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8194.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8194/head:pull/8194

PR: https://git.openjdk.java.net/jdk/pull/8194