Avoid duplicate results using in-barriers

Author: owen-mc

go/ql/lib/semmle/go/security/BrokenCryptoAlgorithmQuery.qll

@@ -24,6 +24,8 @@ private module BrokenCryptoAlgorithmConfig implements DataFlow::ConfigSig {
 
   predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
 
+  predicate isBarrierIn(DataFlow::Node node) { isSource(node) }
+
   predicate isBarrier(DataFlow::Node node) { node instanceof Sanitizer }
 
   predicate observeDiffInformedIncrementalMode() { any() }