LibCompress: Write Deflate window size in the Zlib header

Previously we said that the window size was always 512 bytes, which
caused errors during decompressing in apps outside of Serenity that
actually use this information.
Now, the value is always 7 (32 KiB).

Fixes: #14503

Userland/Libraries/LibCompress/Zlib.cpp

@@ -84,9 +84,15 @@ ZlibCompressor::~ZlibCompressor()
 
 void ZlibCompressor::write_header(ZlibCompressionMethod compression_method, ZlibCompressionLevel compression_level)
 {
+    u8 compression_info = 0;
+    if (compression_method == ZlibCompressionMethod::Deflate) {
+        compression_info = AK::log2(DeflateCompressor::window_size) - 8;
+        VERIFY(compression_info <= 7);
+    }
+
     ZlibHeader header {
         .compression_method = compression_method,
-        .compression_info = 0,
+        .compression_info = compression_info,
         .check_bits = 0,
         .present_dictionary = false,
         .compression_level = compression_level,