Add getConfiguredTargetKey method to TargetAndConfiguration.

PiperOrigin-RevId: 313641582
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java b/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
index a08bc18..c042a1c 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
@@ -287,12 +287,7 @@
 
     List<ConfiguredTargetKey> topLevelCtKeys =
         topLevelTargetsWithConfigs.stream()
-            .map(
-                node ->
-                    ConfiguredTargetKey.builder()
-                        .setLabel(node.getLabel())
-                        .setConfiguration(node.getConfiguration())
-                        .build())
+            .map(TargetAndConfiguration::getConfiguredTargetKey)
             .collect(Collectors.toList());
 
     Multimap<Pair<Label, String>, BuildConfiguration> aspectConfigurations =