This changes `memalign` (and `posix_memalign`) so that it uses an
allocation method with the same selection criteria (checking
`malloc_alwaysinternal_limit` and picking one of:
- always MALLOC_CAP_INTERNAL
- MALLOC_CAP_INTERNAL first with fallback
- MALLOC_CAP_SPIRAM first with fallback
`malloc_alwaysinternal_limit` is in turn set by the options
`CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL` and
`CONFIG_SPRIAM_USE_CAPS_ALLOC`.
This notably affects folks using esp-rs to build rust code for the
esp-idf, as all allocations from rust use `memalign`.
Merges https://github.com/espressif/esp-idf/pull/12375
9e1e245477