Fix trivial warnings

* Fix resource closure warning in lambda by assigning to a final var
  outside
* Fix deprecation warning by suppressing the use of the deprecated
  method
* Add missing serialVersionUID to Serializable anonymous inner class

src/main/java/org/apache/accumulo/testing/continuous/ContinuousInputFormat.java

@@ -143,6 +143,7 @@ private Key genKey(CRC32 cksum) {
 
         byte[] fam = genCol(random.nextInt(maxFam));
         byte[] qual = genCol(random.nextInt(maxQual));
+        @SuppressWarnings("deprecation")
         byte[] cv = visibilities.get(random.nextInt(visibilities.size())).flatten();
 
         if (cksum != null) {

src/main/java/org/apache/accumulo/testing/performance/tests/YieldingScanExecutorPT.java

@@ -220,7 +220,8 @@ private TestExecutor<Long> startLongScans(Environment env, String tableName, Ato
     TestExecutor<Long> longScans = new TestExecutor<>(NUM_LONG_SCANS);
 
     for (int i = 0; i < NUM_LONG_SCANS; i++) {
-      longScans.submit(() -> scan(tableName, env.getClient(), stop, fpi.next()));
+      final var client = env.getClient();
+      longScans.submit(() -> scan(tableName, client, stop, fpi.next()));
     }
     return longScans;
   }

src/main/java/org/apache/accumulo/testing/randomwalk/shard/ExportIndex.java

@@ -123,6 +123,8 @@ public void visit(State state, RandWalkEnv env, Properties props) throws Excepti
   private static HashMap<String,String> getPropsFromTable(String tableName, RandWalkEnv env)
       throws AccumuloException, TableNotFoundException {
     return new HashMap<>() {
+      private static final long serialVersionUID = 1L;
+
       {
         for (var entry : env.getAccumuloClient().tableOperations().getProperties(tableName))
           put(entry.getKey(), entry.getValue());