src: zlib: revert concatenated-stream changes

Revert "src: fix windows build error" and "zlib: support
concatenated gzip files".

This reverts commits be413ac7
and 1183ba47.

Treating subsequent bytes as a concatenated zlib stream
breaks npm install.

Conflicts:
	test/parallel/test-zlib-from-multiple-gzip-with-garbage.js
	test/parallel/test-zlib-from-multiple-gzip.js
	test/parallel/test-zlib-from-multiple-huge-gzip.js

Fixes: https://github.com/joyent/node/issues/8962
PR-URL: https://github.com/iojs/io.js/pull/240


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>