Follow up to D129386 where libc++ naming conventions were made consistent.
This changes the pattern to not rely on the internal name (`__cc` or `__cc_`),
and instead uses a pattern to check that the child has the form:
```
[0] = {
first = ...
```
Thanks to @rupprecht for pointing out this issue: https://reviews.llvm.org/D133259#3773120
Reviewed By: rupprecht
Differential Revision: https://reviews.llvm.org/D133395
8f121a3f18