When a shard becomes search active then trigger a refresh instead of waiting for the next scheduled refresh.
The `IndexShard#awaitShardSearchActive(...)` method registers a refresh listener and then often waits for the refresh scheduler to trigger a refresh. By default this is one second. In order to avoid increasing the query time of the Search API, the mentioned method should trigger a refresh instead for waiting it to happen.

As part of this change we also need to disable the refresh scheduler completely. Otherwise we run at risk of running two refreshes next after each other. One triggered from making shard search active and one from the refresh scheduler.  



server/src/main/java/org/elasticsearch/index/shard/IndexShard.java
*
     * @see #acquireReplicaOperationPermit(long, long, long, ActionListener, String)
     * @see RecoveryTarget#indexTranslogOperations(List, int, long, long, RetentionLeases, long, ActionListener)
     */
    public void advanceMaxSeqNoOfUpdatesOrDeletes(long seqNo) {
        getEngine().advanceMaxSeqNoOfUpdatesOrDeletes(seqNo);
    }
    /**
     * Performs the pre-closing checks on the {@link IndexShard}.
     *
     * @throws IllegalStateException if the sanity checks failed
     */
    public void verifyShardBeforeIndexClosing() throws IllegalStateException {
        getEngine().verifyEngineBeforeIndexClosing();
    }
    RetentionLeaseSyncer getRetentionLeaseSyncer() {
        return retentionLeaseSyncer;
    }
    public long getRelativeTimeInNanos() {
        return relativeTimeInNanosSupplier.getAsLong();
    }
    @Override
    public String toString() {
        return "IndexShard(shardRouting=" + shardRouting + ")";
    }
    public void waitForSegmentGeneration(long segmentGeneration, ActionListener<Long> listener) {
        getEngine().addSegmentGenerationListener(segmentGeneration, listener);
    }
}