ssue #19183: Implement PEP 456 'secure and interchangeable hash algorithm'.
Python now uses SipHash24 on all major platforms.
Issue #19183: test_gdb's test_dict was failing on some machines as the order or dict keys has changed again.
Issue #19183: Fix repr() tests of test_gdb, hash() is now platform dependent
Issue #19183: too many tests depend on the sort order of repr().
The bitshift and xor op for 32bit builds has changed the order of hash values.