Error on multiple default blocks in a switch

Part of RFC: https://wiki.php.net/rfc/switch.default.multiple
Merge branch 'pull-request/808'
Remove two more always-true conditions
Remove HASH_NEXT_INSERT flag

We already pass ht->nNextFreeElement and the rest is handled by
ZEND_HASH_ADD.
Drop BC alias HASH_NON_EXISTANT
fixed signed/unsigned mismatch warning
fix signed/unsigned mismatch warnings
fixed type
redo the fix casting to size_t where applicable
redo the fix casting to size_t
redo the fix with cast to size_t
fix signed/unsigned mismatch
fix signed/unsigned mismatch
fix signed/unsigned mismatch
fix signed/unsigned mismatch
optimized colision list traverse
Use runtime-cache to avoid hash lookups in BIND_GLOBAL instruction
Merge branch 'master' of git://github.com/php/php-src