Revert "[lldb] Fix crash missing MSInheritanceAttr on CXXRecordDecl with DWARF on Windows" (#113498)

Reverts #112928

This is because it broke greendragon:
SymbolFile/DWARF/x86/member-pointers.cpp

Author: rastogishubham

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -2771,9 +2771,6 @@ static bool GetCompleteQualType(clang::ASTContext *ast,
         ast, llvm::cast<clang::AttributedType>(qual_type)->getModifiedType(),
         allow_completion);
 
-  case clang::Type::MemberPointer:
-    return !qual_type.getTypePtr()->isIncompleteType();
-
   default:
     break;
   }