[libc-commits] [libc] Revert "[libc] Breakup freelist_malloc into separate files" (PR #119749)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

```
/usr/bin/ld: projects/libc/fuzzing/__support/libc.fuzzing.__support.freelist_heap_fuzz: hidden symbol `__llvm_libc_heap_limit' isn't defined
```

https://github.com/llvm/llvm-project/pull/119749