Make SkyQueryEnvironment more efficient retrieving the labels.

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MOS_MIGRATED_REVID=101021838

src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java

diff --git a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
index db8ed2d..4e79439 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
@@ -174,7 +174,7 @@
   }
 
   private Set<Label> getAllowedDeps(Rule rule) {
-    Set<Label> allowedLabels = new HashSet<>(rule.getLabels(dependencyFilter));
+    Set<Label> allowedLabels = new HashSet<>(rule.getTransitions(dependencyFilter).values());
     allowedLabels.addAll(rule.getVisibility().getDependencyLabels());
     // We should add deps from aspects, otherwise they are going to be filtered out.
     allowedLabels.addAll(rule.getAspectLabelsSuperset(dependencyFilter));