[lldb][Formatters] Make libc++ and libstdc++ std::shared_ptr formatters consistent with each other (#147165)

This patch adjusts the libcxx and libstdcxx std::shared_ptr formatters
to look the same.

Changes to libcxx:
* Now creates a synthetic child called `pointer` (like we already do for
`std::unique_ptr`)

Changes to libstdcxx:
* When asked to dereference the pointer, cast the type of the result
ValueObject to the element type (which we get from the template argument
to std::shared_ptr).
Before:
```
(std::__shared_ptr<int, __gnu_cxx::_S_atomic>::element_type) *foo = 123
```
After:
```
(int) *foo = 123
```

Tested in https://github.com/llvm/llvm-project/pull/147141

0 files changed, 0 insertions, 0 deletions