Remove incorrect negation from set-addition test.

Change-Id: I194e731e67ecab533820accb2041e413dfc47c65
diff --git a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
index 451529f..89c917a 100644
--- a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
+++ b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
@@ -1655,7 +1655,7 @@
       return;
     }
     if (clazz.isProgramClass()) {
-      if (!instantiatedLambdas.add(clazz.asProgramClass(), KeepReason.instantiatedIn(method))) {
+      if (instantiatedLambdas.add(clazz.asProgramClass(), KeepReason.instantiatedIn(method))) {
         populateInstantiatedTypesCache(clazz.asProgramClass());
       }
     }