Convert ActionLookupKey implementations to directly implement SkyKey, removing the layer of indirection of getting SkyKey out of ActionLookupKey, which uses more memory for no reason.

PiperOrigin-RevId: 181658615
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ConfiguredTargetValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/ConfiguredTargetValue.java
index a11e27a..fc4ebd6 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ConfiguredTargetValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ConfiguredTargetValue.java
@@ -100,13 +100,13 @@
 
   @VisibleForTesting
   public static SkyKey key(Label label, BuildConfiguration configuration) {
-    return key(new ConfiguredTargetKey(label, configuration));
+    return ConfiguredTargetKey.of(label, configuration);
   }
 
   static ImmutableList<SkyKey> keys(Iterable<ConfiguredTargetKey> lacs) {
     ImmutableList.Builder<SkyKey> keys = ImmutableList.builder();
     for (ConfiguredTargetKey lac : lacs) {
-      keys.add(key(lac));
+      keys.add(lac);
     }
     return keys.build();
   }