RFR: 8366517: `DateFormatSymbols(Locale)` throws NPE if `Locale` argument is null [v3]

[Naoto Sato]

> Adding a `@throws` clause for NPE in `java.text.DateFormatSymbols(Locale)` constructor. The bug suggests it should  throw a `MissingResourceException`, but I don't think we can change this long standing behavior. Instead, explicitly specify the NPE in the javadoc.

Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:

  Further requireNonNull()

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27060/files
  - new: https://git.openjdk.org/jdk/pull/27060/files/7b3d4e00..d7cb9566

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27060&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27060&range=01-02

  Stats: 14 lines in 4 files changed: 11 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/27060.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27060/head:pull/27060

PR: https://git.openjdk.org/jdk/pull/27060