Update Zlib to version 1.2.8

merge the latest open source zlib into chromium external projects
Version 1.2.8 fixes a very rare bug in decompression. All users are encouraged to upgrade immediately. Version 1.2.8 also has these improvements:
- Add new inflateGetDictionary() function
- Fix bug where gzopen() immediately followed by gzclose() would write an empty file instead of an empty gzip stream.
- Fix bug in gzclose() when gzwrite() runs out of memory Version 1.2.7 has many portability improvements over 1.2.6, and has these enhancements:
- Fix bug in gzclose_w() when gzwrite() fails to allocate memory
- Add "x" (O_EXCL) and "e" (O_CLOEXEC) modes support to gzopen()
- Add gzopen_w() in Windows for wide character path names
- Fix type mismatch between get_crc_table() and crc_table Version 1.2.6 has many changes over 1.2.5, including these improvements:
- gzread() can now read a file that is being written concurrently
- gzgetc() is now a macro for increased speed
- Added a 'T' option to gzopen() for transparent writing (no compression)
- Added deflatePending() to return the amount of pending output
- Allow deflateSetDictionary() and inflateSetDictionary() at any time in raw mode
- deflatePrime() can now insert bits in the middle of the stream
- ./configure now creates a configure.log file with all of the results
- Added a ./configure --solo option to compile zlib with no dependency on any libraries
- Fixed a problem with large file support macros
- Fixed a bug in contrib/puff
- Many portability improvements

BUG=610615 R=gavinp@chromium.org

Review-Url: https://codereview.chromium.org/2084863002
Cr-Original-Commit-Position: refs/heads/master@{#401538}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: ca1c569cff20aa43a42816791744d847c7d788de