Remove unused typelist constructs from TypeList.h (#194352)

These constructs in `torch/headeronly/util/TypeList.h` have zero in-tree
users outside their own unit test: `filter`, `count_if`, `map`, `last`,
`reverse`, `find_if`, `map_types_to_values` (and its `detail::type_`
helper), and `false_higher_t` (only used by `find_if`'s error case).
Removed together with the matching unit-test sections, the
`torch::headeronly` re-export entries, and their `torch/header_only_apis.txt`
entries. `take`/`drop` and `drop_if_nonempty_t` are kept (the former used
by gaudi-pytorch-bridge, the latter by `c10/core/DispatchKeySet.h`).

Test Plan: trimmed `test_typelist.cpp` still runs in CI; grep confirms
zero remaining references to the deleted constructs.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/194352
Approved by: https://github.com/janeyx99