Revert "Adding GDB PrettyPrinter for mlir::Identifier."

This reverts commit 9e9e6e698d8ef5dc5b7576058f2022aab2534a52.

This commit is causing builds that include the 'debuginfo-tests' project to
fail.

Apple has a public bot which shows the failure:
http://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/23667/console

GitOrigin-RevId: 485e6db8729383345da9796218d99843449057ac
5 files changed