[lldb] Fix crash missing MSInheritanceAttr with DWARF on Windows (#112928)
Member pointers refer to data or function members of a `CXXRecordDecl` and
require a `MSInheritanceAttr` in order to be complete. Without that we
cannot calculate their size in memory. The attempt has been causing a crash
further down in the clang AST context. In order to implement the feature,
DWARF will need a new attribtue to convey the information. For the moment,
this patch teaches LLDB to handle to situation and avoid the crash.