[error prone] Suppress NonAtomicVolatileUpdate in SimpleLruCache

We don't need to update time atomically since it's only used to order
cache entries in LRU order.

Change-Id: I756fa6d90b180c519bf52925f134763744f2c1f1
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/util/SimpleLruCache.java

@@ -162,7 +162,7 @@ public class SimpleLruCache<K, V> {
 	public V get(Object key) {
 		Entry<K, V> entry = map.get(key);
 		if (entry != null) {
-			entry.lastAccessed = ++time;
+			entry.lastAccessed = tick();
 			return entry.value;
 		}
 		return null;
@@ -186,13 +186,18 @@ public class SimpleLruCache<K, V> {
 	 *             if the specified key or value is null
 	 */
 	public V put(@NonNull K key, @NonNull V value) {
-		map.put(key, new Entry<>(key, value, ++time));
+		map.put(key, new Entry<>(key, value, tick()));
 		if (map.size() > maximumSize) {
 			purge();
 		}
 		return value;
 	}
 
+	@SuppressWarnings("NonAtomicVolatileUpdate")
+	private long tick() {
+		return ++time;
+	}
+
 	/**
 	 * Returns the current size of this cache
 	 *