Add back a feature that was available in the old heap implementation
in release/v2.1 and earlier: keep track of which task allocates each
block from the heap. The task handle is conditionally added as
another word in the heap poisoning header under this configuration
option CONFIG_HEAP_TASK_TRACKING.
To allow custom monitoring and debugging code to be added, add helper
functions in multi_heap.c and multi_heap_poisoning.c to provide access
to information in the block headers.
During a call to multi_heap_malloc(), if both these conditions were true:
- That heap only has one block large enough for the allocation
(this is always the case if the heap is unfragmented).
- Another allocation is simultaneously occurring in the same heap.
... multi_heap_malloc() could incorrectly return NULL.
This caused IDF heap_caps_malloc() and malloc() to also fail, particularly
often if only one or two heaps had space for the allocation (otherwise
heap_caps_malloc() fails over to the next heap).
New multi_heap code has proven effective at aborting when buffer overruns occur,
but it's currently hard to debug the stack traces from these failures.
