Allow FST builder to use different writer (#12543) (#12624)

* Move size() to FSTStore

* Remove size() completely

* Allow FST builder to use different DataOutput

* access BytesStore byte[] directly for copying

* Rename BytesStore

* Change class to final

* Reorder methods

* Remove unused methods

* Rename truncate to setPosition() and remove skipBytes()

* Simplify the writing operations

* Update comment

* remove unused parameter

* Simplify BytesStore operation

* tidy code

* Rename copyBytes to writeTo

* Simplify BytesStore operations

* Embed writeBytes() to FSTCompiler

* Fix the write bytes method

* Remove the default block bits constant

* add assertion

* Rename method parameter names

* Move reverse to FSTCompiler

* Revert setPosition call

* Address comments

* Return immediately when writing 0 bytes

* Add comment &

* Rename variables

* Fix the compile error

* Remove isReadable()

* Remove isReadable()

* Optimize ReadWriteDataOutput

* tidy code

* Freeze the DataOutput once finished()

* Refactor

* freeze the DataOutput before use

* Address comments and add off-heap FST tests

* Remove the hardcoded random

* Ignore the Test2BFSTOffHeap test

* Simplify ReadWriteDataOutput

* Update Javadoc

* Address comments

Author: dungba88

lucene/core/src/java/org/apache/lucene/codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java

@@ -16,6 +16,8 @@
  */
 package org.apache.lucene.codecs.lucene90.blocktree;
 
+import static org.apache.lucene.util.fst.FSTCompiler.getOnHeapReaderWriter;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -525,7 +527,7 @@ public void compileIndex(
               // Disable suffixes sharing for block tree index because suffixes are mostly dropped
               // from the FST index and left in the term blocks.
               .suffixRAMLimitMB(0d)
-              .bytesPageBits(pageBits)
+              .dataOutput(getOnHeapReaderWriter(pageBits))
               .build();
       // if (DEBUG) {
       //  System.out.println("  compile index for prefix=" + prefix);