Revert "Add also Py_CLEAR to Misc/stable_abi.toml"

This reverts commit 2373d5a.

Author: vstinner

Doc/data/stable_abi.dat

@@ -1872,10 +1872,6 @@
 [function.PyThread_start_new_thread]
     added = '3.2'
 
-# Python 3.2 macros
-[macro.Py_CLEAR]
-    added = '3.2'
-
 
 ### Python 3.3 ##############################################################