Use C++17 aligned memory allocation

[smithsg84]

Use C++17 aligned memory allocation rather than platform/compiler allocators

With the adoption of C++17 requirement for RAJA the standard aligned memory allocator (std::aligned_alloc) is available and can replace platform / compiler specific options. This PR removes CMake checks for the platform allocators and simplifies the aligned memory allocator wrappers.

• This PR is a refactoring
• It does the following (modify list as needed):
  • Refactors the internal aligned memory allocators to use the std allocators.

Discussion on removal is in a prior cmake fix that has been closed #1985. This PR replaces that change with a more complete change.

[smithsg84]

@MrBurmark @artv3 Based on discussion in #1985 I have removed the old checks for aligned memory allocators and replaced using the C++17 aligned allocators. Simple testing showed no measurable performance difference between the posix_memalign and std::aligned_alloc.

[smithsg84]

Deep sigh, Windows MSVC compiler does not support std::aligned_alloc so the platform specific calls are needed.

[smithsg84]

Closing PR.

Windows MSVC compiler does not support std::aligned_alloc as of 2/5/2026, see notes section.

MacOS CI tests were failing when using the std::aligned_alloc allocator.