RFR: 8247781: Day periods support [v2]

[Naoto Sato]

> Hi,
> 
> Please review the changes for the subject issue. This is to enhance the java.time package to support day periods, such as "in the morning", defined in CLDR. It will add a new pattern character 'B' and its supporting builder method. The motivation and its spec are in this CSR:
> 
> https://bugs.openjdk.java.net/browse/JDK-8254629
> 
> Naoto

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

  Addressed the following comments:
  - https://github.com/openjdk/jdk/pull/938#discussion_r515003422
  - https://github.com/openjdk/jdk/pull/938#discussion_r515005296
  - https://github.com/openjdk/jdk/pull/938#discussion_r515008862
  - https://github.com/openjdk/jdk/pull/938#discussion_r515030268
  - https://github.com/openjdk/jdk/pull/938#discussion_r515030880
  - https://github.com/openjdk/jdk/pull/938#discussion_r515032002
  - https://github.com/openjdk/jdk/pull/938#discussion_r515036803
  - https://github.com/openjdk/jdk/pull/938#discussion_r515037626
  - https://github.com/openjdk/jdk/pull/938#discussion_r515038069
  - https://github.com/openjdk/jdk/pull/938#discussion_r515039056

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/938/files
  - new: https://git.openjdk.java.net/jdk/pull/938/files/7ac5fa03..6e1eade7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=938&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=938&range=00-01

  Stats: 99 lines in 3 files changed: 48 ins; 2 del; 49 mod
  Patch: https://git.openjdk.java.net/jdk/pull/938.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/938/head:pull/938

PR: https://git.openjdk.java.net/jdk/pull/938