bpo-36611: Fix test_sys.test_getallocatedblocks() (GH-12797)
Fix test_sys.test_getallocatedblocks() when tracemalloc is enabled.
If the name of Python memory allocators cannot get read, consider
that pymalloc is disabled.
Fix the following error:
./python -X tracemalloc -m test test_sys -v -m test_getallocatedblocks
ERROR: test_getallocatedblocks (test.test_sys.SysModuleTest)
------------------------------------------------------------
Traceback (most recent call last):
File "Lib/test/test_sys.py", line 770, in test_getallocatedblocks
alloc_name = _testcapi.pymem_getallocatorsname()
RuntimeError: cannot get allocators name2 files changed