So it's possible to get debug messages in test_tracemalloc.

Issue #26588.

Try to debug random failure on buildbots.

Timestamps should help to debug slow buildbots, and timeout and hang on
buildbots.

Issue #26530:

* Add C functions _PyTraceMalloc_Track() and _PyTraceMalloc_Untrack() to track
  memory blocks using the tracemalloc module.
* Add _PyTraceMalloc_GetTraceback() to get the traceback of an object.

Issue #26588:

* The _tracemalloc now supports tracing memory allocations of multiple address
  spaces (domains).
* Add domain parameter to tracemalloc_add_trace() and
  tracemalloc_remove_trace().
* tracemalloc_add_trace() now starts by removing the previous trace, if any.
* _tracemalloc._get_traces() now returns a list of (domain, size,
  traceback_frames): the domain is new.
* Add tracemalloc.DomainFilter
* tracemalloc.Filter: add an optional domain parameter to the constructor and a
  domain attribute
* Sublte change: use Py_uintptr_t rather than void* in the traces key.
* Add tracemalloc_config.use_domain, currently hardcoded to 1

Issue #26588: Remove _Py_hashtable_delete() from hashtable.h since the function
is not used. Keep the C code in hashtable.c as commented code if someone needs
it later.

Issue #26588: Remove copy_data, free_data and get_data_size callbacks from
hashtable.h. These callbacks are not used in Python and makes the code more
complex.

Remove also the _Py_HASHTABLE_ENTRY_DATA_AS_VOID_P() macro which uses an unsafe
pointer dereference (can cause memory alignment issue). Replace the macro usage
with _Py_HASHTABLE_ENTRY_READ_DATA() which is implemented with the safe
memcpy() function.

Issue #26588: hashtable.h now supports keys of any size, not only
sizeof(void*). It allows to support key larger than sizeof(void*), but also to
use less memory for key smaller than sizeof(void*).

uuid.uuid4() always uses os.urandom() after 756d040aa8e8.

Patch by jgauthier.

Patch by Andrew Szeto.

Without the patch, line 1010 of Lib/datetime.py wasn't covered
by the test suite.

Patch by Colin Williams.

casting iobase_finalize to destructor is not needed

Issue #26590: support.check_warnings() stores warnins, but ResourceWarning now
comes with a reference to the socket object which indirectly keeps the socket
alive.

Issue #26590: Implement a safe finalizer for the _socket.socket type. It now
releases the GIL to close the socket. Use PyErr_ResourceWarning() to raise the
ResourceWarning to pass the socket object to the warning logger, to get the
traceback where the socket was created (allocated).

Change pushed by mistake, the patch is still under review :-/

"""
_tracemalloc: add domain to trace keys

* hashtable.h: key has now a variable size
* _tracemalloc uses (pointer: void*, domain: unsigned int) as key for traces
"""

Issue #26574: Optimize bytes.replace(b'', b'.') and
bytearray.replace(b'', b'.'): up to 80% faster. Patch written by Josh Snider.

Initial patch by Peter Inglesby.

* hashtable.h: key has now a variable size
* _tracemalloc uses (pointer: void*, domain: unsigned int) as key for traces