Fixed PHP-792: Memory leak on 32bit platforms with native_long enabled and reading an INT64.
Fixed error code, and add a check for it to the test.

Code 1 was already meaning something else.
Merged pull request #420
Fixed PHP-800: Do not overload error codes.

Making tests for this is tricky, as you need a > 64MB document... not sure if
it's even worth testing.
Merged pull request #433