(index-reverse) Entry Sources reset() their LongQueryBuffer

Previously this was the responsibility of the caller, which lead to the possibility of passing in improperly prepared buffers and receiving bad outcome

code/index/index-reverse/java/nu/marginalia/index/FullIndexEntrySource.java

@@ -36,6 +36,7 @@ public class FullIndexEntrySource implements EntrySource {
 
     @Override
     public void read(LongQueryBuffer buffer) {
+        buffer.reset();
         buffer.end = min(buffer.end, endOffset - pos);
         reader.readData(buffer.data, buffer.end, pos);
         pos += buffer.end;

code/index/index-reverse/java/nu/marginalia/index/PrioIndexEntrySource.java

@@ -42,6 +42,7 @@ public class PrioIndexEntrySource implements EntrySource {
     @SneakyThrows
     @SuppressWarnings("preview")
     public void read(LongQueryBuffer buffer) {
+        buffer.reset();
         buffer.end = min(buffer.end, endOffsetL - posL);
 
         var byteBuffer = buffer.data.getMemorySegment().asByteBuffer();

code/index/query/java/nu/marginalia/index/query/IndexQuery.java

@@ -73,8 +73,6 @@ public class IndexQuery {
 
     private boolean fillBuffer(LongQueryBuffer dest) {
         for (;;) {
-            dest.reset();
-
             EntrySource source = sources.get(si);
             source.read(dest);