fix bugs in Deflater and DeflaterOutputStream

Previously, Deflater.deflate would pass Z_SYNC_FLUSH to zlib
unconditionally, which caused the output to be enormous when setInput
was called repeatedly with very small input buffers.  In order to
allow zlib to buffer output and thereby maximize compression, we must
use Z_NO_FLUSH until Deflater.finish is called, at which point we
switch to Z_FINISH.  We also modify DeflaterOutputStream.close to call
Deflater.finish and write any remaining output to the wrapped stream.

classpath/java/util/zip/DeflaterOutputStream.java

@@ -52,23 +52,25 @@ public class DeflaterOutputStream extends OutputStream {
     } else if (length == 0) {
       return;
     }
-    
-    for (int i = 0; i < length; i+= buffer.length) {
-      deflater.setInput(b, offset + i, Math.min(buffer.length, length - i));
-      while (deflater.getRemaining() > 0) {
-        try {
-          int len = deflater.deflate(buffer, 0, buffer.length);
-          if (len > 0) {
-            out.write(buffer, 0, len);
-          }
-        } catch (DataFormatException e) {
-          e.printStackTrace();
-        }
-      }
+
+    deflater.setInput(b, offset, length);
+    while (deflater.getRemaining() > 0) {
+      deflate();
+    }
+  }
+
+  private void deflate() throws IOException {
+    int len = deflater.deflate(buffer, 0, buffer.length);
+    if (len > 0) {
+      out.write(buffer, 0, len);
     }
   }
 
   public void close() throws IOException {
+    deflater.finish();
+    while (! deflater.finished()) {
+      deflate();
+    }
     out.close();
     deflater.dispose();
   }