C#: Get rid of the isOwnInstanceAccess based on ReturnStmt.

java/ql/src/utils/model-generator/CaptureSummaryModels.qll

@@ -9,9 +9,9 @@ import CaptureSummaryModelsSpecific
  * Gets the summary model of `api`, if it follows the `fluent` programming pattern (returns `this`).
  */
 string captureQualifierFlow(TargetApi api) {
-  exists(ReturnStmt rtn |
-    rtn.getEnclosingCallable() = api and
-    isOwnInstanceAccess(rtn)
+  exists(ReturnNodeExt ret |
+    api = returnNodeEnclosingCallable(ret) and
+    isOwnInstanceAccessNode(ret)
   ) and
   result = asValueModel(api, qualifierString(), "ReturnValue")
 }

java/ql/src/utils/model-generator/CaptureSummaryModelsSpecific.qll

@@ -10,7 +10,10 @@ import semmle.code.java.dataflow.internal.DataFlowPrivate
 import semmle.code.java.dataflow.InstanceAccess
 import ModelGeneratorUtils
 
-predicate isOwnInstanceAccess(ReturnStmt rtn) { rtn.getResult().(ThisAccess).isOwnInstanceAccess() }
+pragma[inline]
+Callable returnNodeEnclosingCallable(ReturnNodeExt ret) {
+  result = getNodeEnclosingCallable(ret).asCallable()
+}
 
 predicate isOwnInstanceAccessNode(ReturnNode node) {
   node.asExpr().(ThisAccess).isOwnInstanceAccess()