bpo-39489: Remove COUNT_ALLOCS special build (GH-18259)

Remove:

* COUNT_ALLOCS macro
* sys.getcounts() function
* SHOW_ALLOC_COUNT code in listobject.c
* SHOW_TRACK_COUNT code in tupleobject.c
* PyConfig.show_alloc_count field
* -X showalloccount command line option
* @test.support.requires_type_collecting decorator
diff --git a/Python/clinic/sysmodule.c.h b/Python/clinic/sysmodule.c.h
index daca0e6..4615eba 100644
--- a/Python/clinic/sysmodule.c.h
+++ b/Python/clinic/sysmodule.c.h
@@ -758,27 +758,6 @@
     return return_value;
 }
 
-#if defined(COUNT_ALLOCS)
-
-PyDoc_STRVAR(sys_getcounts__doc__,
-"getcounts($module, /)\n"
-"--\n"
-"\n");
-
-#define SYS_GETCOUNTS_METHODDEF    \
-    {"getcounts", (PyCFunction)sys_getcounts, METH_NOARGS, sys_getcounts__doc__},
-
-static PyObject *
-sys_getcounts_impl(PyObject *module);
-
-static PyObject *
-sys_getcounts(PyObject *module, PyObject *Py_UNUSED(ignored))
-{
-    return sys_getcounts_impl(module);
-}
-
-#endif /* defined(COUNT_ALLOCS) */
-
 PyDoc_STRVAR(sys__getframe__doc__,
 "_getframe($module, depth=0, /)\n"
 "--\n"
@@ -988,11 +967,7 @@
     #define SYS_GETTOTALREFCOUNT_METHODDEF
 #endif /* !defined(SYS_GETTOTALREFCOUNT_METHODDEF) */
 
-#ifndef SYS_GETCOUNTS_METHODDEF
-    #define SYS_GETCOUNTS_METHODDEF
-#endif /* !defined(SYS_GETCOUNTS_METHODDEF) */
-
 #ifndef SYS_GETANDROIDAPILEVEL_METHODDEF
     #define SYS_GETANDROIDAPILEVEL_METHODDEF
 #endif /* !defined(SYS_GETANDROIDAPILEVEL_METHODDEF) */
-/*[clinic end generated code: output=decd687b7631de4b input=a9049054013a1b77]*/
+/*[clinic end generated code: output=39eb34a01fb9a919 input=a9049054013a1b77]*/