[clang] [AST] Iterate redecls starting from the canonical one in getRawCommentsForAnyRedecl() (PR #108475)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

Hmm, quite a few things are failing:

```
Failed Tests (14):
  Clang :: CXX/drs/cwg28xx.cpp
  Clang :: CXX/drs/cwg7xx.cpp
  Clang :: CXX/temp/temp.spec/temp.expl.spec/p2-20.cpp
  Clang :: CXX/temp/temp.spec/temp.expl.spec/p8.cpp
  Clang :: Index/index-file.cpp
  Clang :: PCH/cxx-ms-function-specialization-class-scope.cpp
  Clang :: PCH/cxx-templates.cpp
  Clang :: SemaCXX/ms-exception-spec.cpp
  Clang :: SemaTemplate/explicit-specialization-member.cpp
  Clang :: SemaTemplate/function-template-specialization.cpp
  Clang :: SemaTemplate/instantiate-member-specialization.cpp
  Clang :: SemaTemplate/member-specialization.cpp
  Clang :: SemaTemplate/ms-function-specialization-class-scope.cpp
  Clangd Unit Tests :: ./ClangdTests/DefineInlineTest/AddInline
```

https://github.com/llvm/llvm-project/pull/108475