zlib: Fix a bug when getting a gzip header extra field with inflate().

If the extra field was larger than the space the user provided with
inflateGetHeader(), and if multiple calls of inflate() delivered
the extra header data, then there could be a buffer overflow of the
provided space. This commit assures that provided space is not
exceeded.

(cherry picked from zlib commit eff308af425b67093bab25f80f1ae950166bece1)
(cherry picked from zlib commit 1eb7682f845ac9e9bf9ae35bbfb3bad5dacbd91d)

(cherry picked from commit dc3509f1aafcd966f3dd9226115cf94b691ff3c7)
(cherry picked from commit 2969066f73fc67a614144ac09b9f3f5291937fed)