Revert "HBASE-21905 (addendum): Address compaction races in TestFIFOCompactionPolicy (#2203)"

This reverts commit 839ce8e.

Reverting to apply as HBASE-24846.

Author: bharathv

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/compactions/TestFIFOCompactionPolicy.java

@@ -115,11 +115,6 @@ public static void setEnvironmentEdge() throws Exception {
     EnvironmentEdgeManager.injectEdge(ee);
     Configuration conf = TEST_UTIL.getConfiguration();
     conf.setInt(HStore.BLOCKING_STOREFILES_KEY, 10000);
-    // Expired store file deletion during compaction optimization interferes with the FIFO
-    // compaction policy. The race causes changes to in-flight-compaction files resulting in a
-    // non-deterministic number of files selected by compaction policy. Disables that optimization
-    // for this test run.
-    conf.setBoolean("hbase.store.delete.expired.storefile", false);
     TEST_UTIL.startMiniCluster(1);
   }