fuzz_utils.h: rename max() to Max()
fuzz_utils.h: rename max() to Max()

avoids conflict with windows.h define

Bug: webp:409
Change-Id: I8ae0947365e7071d8ebe1d682c9211882cc2fd89

PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp,webmproject/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp