[libcxx-commits] [libcxx] [libc++] Fix use-after-free during self-assignment (PR #225296)

[Chris Kennelly via libcxx-commits]

ckennelly wrote:

One of the frozen header test runners failed:

```
  # | t.tmp.exe: /__w/llvm-project/llvm-project/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/iterator.pass.cpp:44: void test_self_referencing_range(typename S::size_type) [S = std::string]: Assertion `s == expected' failed.
```

I applied the skip tag since frozen headers, if I understand the nature of the frozen headers, we are unlikely to want to backport this to them.  I can alternatively do some surgery to exclude the test from pre-C++11 builds in the test?

https://github.com/llvm/llvm-project/pull/225296