RFR: 8282081: java.time.DateTimeFormatter: wrong definition of symbol F

[Naoto Sato]

Fixing the definition and implementation of the pattern symbol `F`. Although it is an incompatible change, I believe it is worth the fix. For that, a CSR has been drafted.

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Commit messages:
 - 8282081: java.time.DateTimeFormatter: wrong definition of symbol F

Changes: https://git.openjdk.java.net/jdk/pull/7640/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7640&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282081
  Stats: 5 lines in 3 files changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7640.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7640/head:pull/7640

PR: https://git.openjdk.java.net/jdk/pull/7640