Use fake index in integration tests, allow running against lucene/fake indices

This change wires up the new fake index so that integration tests,
including tests that use pgms can run against it. It adds a new
sys/env setting so that we can choose which index backend test should
be run against. This is inspired by how we handled different NoteDb
migration states in tests while the migration was not completed.

By default, integration tests are now run against the fake index.

We use reflection in pgms to call the fake index so that we can
keep the fake index package's testonly=true flag.

Change-Id: Ic6ebb6587cb8ab0979a0f00d5e3e340d27115c89
diff --git a/javatests/com/google/gerrit/acceptance/pgm/ElasticReindexIT.java b/javatests/com/google/gerrit/acceptance/pgm/ElasticReindexIT.java
index f23cc10..0632241 100644
--- a/javatests/com/google/gerrit/acceptance/pgm/ElasticReindexIT.java
+++ b/javatests/com/google/gerrit/acceptance/pgm/ElasticReindexIT.java
@@ -14,23 +14,15 @@
 
 package com.google.gerrit.acceptance.pgm;
 
-import static com.google.gerrit.elasticsearch.ElasticTestUtils.createAllIndexes;
 import static com.google.gerrit.elasticsearch.ElasticTestUtils.getConfig;
 
 import com.google.gerrit.elasticsearch.ElasticVersion;
 import com.google.gerrit.testing.ConfigSuite;
-import com.google.inject.Injector;
 import org.eclipse.jgit.lib.Config;
 
 public class ElasticReindexIT extends AbstractReindexTests {
-
   @ConfigSuite.Default
   public static Config elasticsearchV7() {
     return getConfig(ElasticVersion.V7_8);
   }
-
-  @Override
-  public void configureIndex(Injector injector) {
-    createAllIndexes(injector);
-  }
 }