<i18n dev> RFR: 8289768: Clean up unused code [v3]

[Daniel Jeliński]

> This patch removes many unused variables and one unused label reported by the compilers when relevant warnings are enabled. 
> 
> The unused code was found by compiling after removing `unused` from the list of disabled warnings for [gcc](https://github.com/openjdk/jdk/blob/master/make/autoconf/flags-cflags.m4#L190) and [clang](https://github.com/openjdk/jdk/blob/master/make/autoconf/flags-cflags.m4#L203), and enabling [C4189](https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-4-c4189?view=msvc-170) MSVC warning.
> 
> I only removed variables that were uninitialized or initialized without side effects. I verified that the removed variables were not used in any `#ifdef`'d code. I checked that the changed code still compiles on Windows, Linux and Mac, both in release and debug versions.

Daniel Jeliński has updated the pull request incrementally with two additional commits since the last revision:

 - Update copyright
 - Remove more unused variables

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9383/files
  - new: https://git.openjdk.org/jdk/pull/9383/files/b4cd5374..da30ef90

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9383&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9383&range=01-02

  Stats: 30 lines in 26 files changed: 0 ins; 4 del; 26 mod
  Patch: https://git.openjdk.org/jdk/pull/9383.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9383/head:pull/9383

PR: https://git.openjdk.org/jdk/pull/9383