Revert "Use partial flushes with miniz_oxide backend"

This reverts commit 58afe33.

Author: fintelia

src/ffi/rust.rs

@@ -136,8 +136,7 @@ impl From<FlushCompress> for MZFlush {
     fn from(value: FlushCompress) -> Self {
         match value {
             FlushCompress::None => Self::None,
-            FlushCompress::Partial => Self::Partial,
-            FlushCompress::Sync => Self::Sync,
+            FlushCompress::Partial | FlushCompress::Sync => Self::Sync,
             FlushCompress::Full => Self::Full,
             FlushCompress::Finish => Self::Finish,
         }