Java: Support MaD barrier guards checking the qualifier.

Author: aschackmull

java/ql/lib/semmle/code/java/dataflow/ExternalFlow.qll

@@ -662,9 +662,10 @@ private module Cached {
       isBarrierGuardNode(n, acceptingvalue, kind, model) and
       n.asNode().asExpr() = e and
       kmp = TMkPair(kind, model) and
-      g.(Call).getAnArgument() = e and
       // gv = convertAcceptingValue(acceptingvalue)
       branch = convertAcceptingValue(acceptingvalue)
+    |
+      g.(Call).getAnArgument() = e or g.(MethodCall).getQualifier() = e
     )
   }