RFR: 8324665: Loose matching of space separators in the lenient date/time parsing mode

[Naoto Sato]

Implementing "loose matching" of space separators in both `java.time.format.DateTimeFormatter` and `java.text.DateFormat` on lenient parsing. This will effectively fix the NNBSP issues on parsing time with am/pm markers introduced with CLDR version 42 (https://inside.java/2023/03/28/quality-heads-up/). A draft CSR has also been drafted.

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Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/17678/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17678&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324665
  Stats: 175 lines in 4 files changed: 169 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17678.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17678/head:pull/17678

PR: https://git.openjdk.org/jdk/pull/17678