This PR adds a summary and synthetic children for `std::unique_ptr` from
MSVC's STL
([NatVis](313964b78a/stl/debugger/STL.natvis (L285-L303))).
As with libc++, the deleter is only shown if it's non-empty.
Tested both the shared_ptr and unique_ptr tests on Windows.
Towards #24834.
I forgot to use the non-synthetic value to check for the `_Ptr` member.
Fixes the test failure from #147575.
---------
Co-authored-by: Michael Buch <michaelbuch12@gmail.com>
This PR adds formatters for `std::shared_ptr` and `std::weak_ptr`. They
are similar to the ones from libc++ and libstdc++.
[Section from MSVC STL
NatVis](313964b78a/stl/debugger/STL.natvis (L512-L578)).
To support debugging with PDB debug info, I had to add an early exit in
`GetDesugaredSmartPointerValue`, because with PDB, LLDB doesn't know
about template types. This isn't an issue here, since the typedef type
is already resolved there, so no casting is needed.
The tests don't check for PDB - maybe this should be changed? I don't
know a good way to do this. PDB has the downside that it resolves
typedefs. Here in particular, the test for `element_type` would need to
be replaced with `User` and `std::string` with
`std::basic_string<char,std::char_traits<char>,std::allocator<char> >`.
Towards #24834.
