OpenSystemsDevelopment / qpdf

… in damaged label tests

- Add `validate()` call to `QPDFNumberTreeObjectHelper` for page label validation.
- Introduce stricter enforcement of dictionary values and validation logic.
- Update damaged page label test to remove `EXPECT_FAILURE`.

…fy logic, and enhance consistency with modern C++ practices.

The old code didn't put one there, and it's not really useful. It just
makes the file (trivially) larger.

Using search and replace.

I decided these were confusing and inconsistent with how JSON works.
They muddle the API rather than improving it.

(patrepl and cleanpatch are my own utilities)

patrepl s/PointerHolder/std::shared_ptr/g {include,libqpdf}/qpdf/*.hh
patrepl s/PointerHolder/std::shared_ptr/g libqpdf/*.cc
patrepl s/make_pointer_holder/std::make_shared/g libqpdf/*.cc
patrepl s/make_array_pointer_holder/QUtil::make_shared_array/g libqpdf/*.cc
patrepl s,qpdf/std::shared_ptr,qpdf/PointerHolder, **/*.cc **/*.hh
git restore include/qpdf/PointerHolder.hh
cleanpatch
./format-code

Run this:

for i in  **/*.cc **/*.c **/*.h **/*.hh; do
  clang-format < $i >| $i.new && mv $i.new $i
done

Use get() and use_count() instead. Add #define
NO_POINTERHOLDER_DEPRECATION to remove deprecation markers for these
only.

This commit also removes all deprecated PointerHolder API calls from
qpdf's code except in PointerHolder's test suite, which must continue
to test the deprecated APIs.