GITHUB-12224: copy KnnGraphTester from Lucene and update related scri…

…pts and instructions (#218)

Co-authored-by: Michael Sokolov <sokolovm@amazon.com>

README.md

@@ -129,3 +129,9 @@ You can create your own line doc file from an arbitrary Wikimedia dump by follow
     # extract titie, timestamp and body text
     cat /data/jawiki/jawiki-20200620-lines.txt | cut -f1,2,3
     ```
+# Running the KNN benchmark
+
+Some knn-related tasks are included in the main benchmarks. If you specifically want to test
+KNN/HNSW there is a script dedicated to that in src/python/knnPerfTest.py which has instructions on
+how to run it in its comments.
+

build.xml

@@ -2,16 +2,22 @@
 
   <property name="data.dir" value="${basedir}/../data"/>
   <property name="tasks.dir" value="${basedir}/tasks"/>
+  <property name="lucene.checkout" value="${basedir}/../lucene"/>
 
   <target name="build">
 
+    <mkdir dir="build"/>
+
     <path id="build.classpath">
       <pathelement location="build"/>
+      <fileset dir="${lucene.checkout}/lucene/core/build/libs/">
+        <include name="*.jar"/>
+      </fileset>
     </path>
 
     <javac srcdir="src/main"
            destdir="build"
-           includes="WikiVectors.java,perf/VectorDictionary.java"
+           includes="KnnGraphTester.java,WikiVectors.java,perf/VectorDictionary.java"
            classpathref="build.classpath"
            includeantruntime="false"/>