Fix to inflate: treat EOF as a character, as in the C code.
Fix to inflate: treat EOF as a character, as in the C code.

closes PR 13489.

In the C code, inflate is allowed to peek at least one character
beyond the extent of a deflated byte sequence.  The thread related to
the bug report of PR 13489 documents that deflate can peek beyond EOF.

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket