Revert "Treat `std::move`, `forward`, and `move_if_noexcept` as builtins."

Revert "Extend support for std::move etc to also cover std::as_const and"
Revert "Update test to handle opaque pointers flag flip."

It crashes on libcxx tests https://lab.llvm.org/buildbot/#/builders/85/builds/8174

This reverts commit fc309010.
This reverts commit a571f82a.
This reverts commit 64c045e2.