[clang-format] [PR44345] Long namespace closing comment is duplicated endlessly

Summary:
https://bugs.llvm.org/show_bug.cgi?id=44345

When namespaces get long the namespace end comment wraps onto the next line

```
namespace would::it::save::you::a::lot::of::time::if_::i::just::gave::up::and_::
    went::mad::now {
void foo();
void bar();
} // namespace
  // would::it::save::you::a::lot::of::time::if_::i::just::gave::up::and_::went::mad::now
```

If clang-format it applied successively it will duplicate the end comment

```
namespace would::it::save::you::a::lot::of::time::if_::i::just::gave::up::and_::
    went::mad::now {
void foo();
void bar();
} // namespace
  // would::it::save::you::a::lot::of::time::if_::i::just::gave::up::and_::went::mad::now
  // would::it::save::you::a::lot::of::time::if_::i::just::gave::up::and_::went::mad::now
```

This revision checks to ensure the end comment is not on the next line before adding yet another comment

Reviewed By: krasimir

Subscribers: cfe-commits

Tags: #clang, #clang-format

Differential Revision: https://reviews.llvm.org/D79935