TrackingAllocator and GcRootArenaAllocator: C++20 fixes

std::allocator<T> deprecates several member typedefs in C++17 and
removes them in C++20, so stop using them:

 * pointer
 * const_pointer
 * reference
 * const_reference

Reduce TrackingAllocatorImpl and GcRootArenaAllocator to what's
required by the Allocator requirements[1]:

 * The only member typedef needed is value_type. All the others are
   optional and were previously delegated to std::allocator<T>, so we
   can rely on the default behavior.

 * The hint parameter for allocate was supposed to be const void*, not
   const T*. It's deprecated now, though.

 * TrackingAllocatorImpl was inheriting from std::allocator<T>, and it
   could have delegated allocate and deallocate to std::allocator<T>,
   but instead it uses malloc/free, so just remove the base class
   entirely.

 * GcRootArenaAllocator: prefer delegation to
   TrackingAllocator<T, kTag> over inheritance.

 * rebind is non-optional because GcRootArenaAllocator and
   TrackingAllocatorImpl's second template parameter is a value, not
   a type (specifically, a value of type AllocatorTag).

 * Remove explicit from the TrackingAllocatorImpl and
   GcRootArenaAllocator copy constructors. The explicit on
   TrackingAllocatorImpl caused a build error when I enabled
   kEnableTrackingAllocator.

[1]: https://en.cppreference.com/w/cpp/named_req/Allocator

Bug: 311052584
Test: art_standalone_libartbase_tests
Test: art_standalone_runtime_tests
Test: remove cpp_std override and build Android
Change-Id: I4e6d4ee418c21fb24974a32129bc08d550a63b86

0 files changed, 0 insertions, 0 deletions