RFR: 8354292: Remove unused PRAGMA_FORMAT_IGNORED

[simon]

The macro PRAGMA_FORMAT_IGNORED is defined in compilerWarnings_gcc.hpp, with default empty definition in compilerWarnings.hpp. It is unused and can be removed.

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

Commit messages:
 - 8354292: removed unused macro PRAGMA_FORMAT_IGNORED.

Changes: https://git.openjdk.org/jdk/pull/24958/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24958&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354292
  Stats: 5 lines in 2 files changed: 0 ins; 5 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24958.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24958/head:pull/24958

PR: https://git.openjdk.org/jdk/pull/24958