gh-115491: Keep some fields valid across allocations in obmalloc (free-threading)#115745
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This avoids overwriting the first few fields in the
PyObjectheader with debug bytes (like0xDDfor dead bytes) in the free-threaded build. These fields may be accessed for a period after an object is deallocated.For simplicity, this skips some of the filling of debug bytes for the "realloc" calls in the free-threaded build, because that case is more complex. The calls that delegate to mimalloc will be filled by mimalloc with debug bytes anyways.
ob_tid,ob_ref_local, andob_ref_sharedfields valid across allocations in free-threaded build #115491