[clang] Fix PS "selective" DLL import/export of vtable & typeinfo (#92579)

Prior to this patch, for "selective" DLL import/export, the vtable &
typeinfo would be imported/exported on the condition that all non-inline
virtual methods are imported/exported. This condition was based upon MS
guidelines related to "selective" DLL import/export.

However, in reality, this condition is too rigid and can result in
undefined vtable & typeinfo symbols for code that builds fine with MSVC.
Therefore, relax this condition to be if any non-inline method is
imported/exported.