bzip2: block size 9 -> 5, reduces memory by 400Kbytes, doesn't affect speed
or compression ratio on all but the largest bytecode files (>1MB)
zip: level 9 -> 6, this speeds up compression time by ~30% but only
degrades the compressed size by a few bytes per megabyte. Those few
bytes aren't worth the effort.
llvm-svn: 17647