[clang-tools-extra] Reapply "[clang-doc] Move Info types into arenas (#190054)" (PR #192495)

[via cfe-commits]

dyung wrote:

I just tried your changes on the bot and it still seems to show the 31 failures:
```
Failed Tests (31):
  Clang Tools :: clang-doc/DR-141990.cpp
  Clang Tools :: clang-doc/basic-project.mustache.test
  Clang Tools :: clang-doc/basic-project.test
  Clang Tools :: clang-doc/builtin_types.cpp
  Clang Tools :: clang-doc/comments-in-macros.cpp
  Clang Tools :: clang-doc/conversion_function.cpp
  Clang Tools :: clang-doc/enum.cpp
  Clang Tools :: clang-doc/json/class-requires.cpp
  Clang Tools :: clang-doc/json/class-template.cpp
  Clang Tools :: clang-doc/json/class.cpp
  Clang Tools :: clang-doc/json/compound-constraints.cpp
  Clang Tools :: clang-doc/json/concept.cpp
  Clang Tools :: clang-doc/json/function-requires.cpp
  Clang Tools :: clang-doc/json/function-specifiers.cpp
  Clang Tools :: clang-doc/json/method-template.cpp
  Clang Tools :: clang-doc/json/namespace.cpp
  Clang Tools :: clang-doc/json/nested-namespace.cpp
  Clang Tools :: clang-doc/mustache-index.cpp
  Clang Tools :: clang-doc/namespace.cpp
  Clang Tools :: clang-doc/single-file-public.cpp
  Clang Tools :: clang-doc/single-file.cpp
  Clang Tools :: clang-doc/templates.cpp
  Clang Tools :: clang-doc/typedef-alias.cpp
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/BitcodeTest/emitNamespaceInfoBitcode
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/BitcodeTest/emitRecordInfoBitcode
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitEnumInfo
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitInlinedFunctionInfo
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitModulePublicLFunctions
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitNamespaceInfo
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitPublicFunctionInternalInfo
  Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest/emitRecordInfo
```
I also built the previous commit in your branch just to confirm, and all of the clang-tools-extra tests passed on that commit.

https://github.com/llvm/llvm-project/pull/192495