undo the Python-optimisationism of assigning bound/unbound methods to local variables when Cython can call a builtin C function instead

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extra : amend_source : 121eadd540f25f9e43f6e6b60853eeab18d11620

let RemoveUnreachableCode discard any PassStatNodes (e.g. added by analysing declaration-only ExprStatNode)

--HG--
extra : rebase_source : 2e86ee2423754e0cfa6e79b33b9570a25a019c01

minor portability tweak: mark non-tiny integer literals as C longs with "L" suffix when passing them into PyInt_FromLong()

avoid accidental duplication of cached Python integer constants when using numbers in different notations

try fixing test failures in int_literals.pyx by removing dependency on Py2/3 specific 'L' postfix of long objects

discard lots of useless code and overhead from try-finally statements that don't need to handle Python exceptions (including C-only with-blocks)

fix problematic constant folding condition in cascaded comparisons (even though it likely doesn't work anyway)

prevent compile time constant folding of non-portable string comparisons (e.g. between bytes and str)

avoid risk of stale pointers by looking up Cython types module on each request (shouldn't hurt much to do it a couple of times during module initialisation)