lib2to3.pgen3.driver.load_grammar() now creates a stable cache file

between runs given the same Grammar.txt input regardless of the hash
randomization setting.

diff --cc Lib/lib2to3/tests/support.py
Simple merge

diff --cc Lib/lib2to3/tests/test_parser.py
Simple merge

diff --cc Misc/NEWS
index fb8a0cb5484595a854d0bf1e7abe584ae5e5adfe,e4991c9decec52a315189ff707a63b976ea7b01e..91a3e8b04daa5b29a711ad1de06100301d47e72e
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -99,8 -46,31 +99,12 @@@ Core and Builtin
  Library
  -------
  
+ - lib2to3.pgen3.driver.load_grammar() now creates a stable cache file
+   between runs given the same Grammar.txt input regardless of the hash
+   randomization setting.
+ 
 +- Issue #28005: Allow ImportErrors in encoding implementation to propagate.
 +
  - Issue #27570: Avoid zero-length memcpy() etc calls with null source
    pointers in the "ctypes" and "array" modules.