overflow bug in SanitizeOptions

`ClipToRange(&result.max_open_files, 64 + kNumNonTableCacheFiles, 50000);`
`ClipToRange(&result.write_buffer_size, 64<<10, 1<<30);`
`ClipToRange(&result.max_file_size, 1<<20, 1<<30);`
`ClipToRange(&result.block_size, 1<<10, 4<<20);`

write_buffer_size=2<<30;
ClipToRange(&result.write_buffer_size, 64<<10, 1<<30);
// assert(write_buffer_size == 1<<30);
// write_buffer_size convert from size_t to int, overflow
assert(write_buffer_size == 64 << 10);