Update code coverage filter

Ix.NET/Source/CodeCoverage.runsettings

@@ -19,9 +19,10 @@ Included items must then not match any entries in the exclude list to remain inc
             <ModulePaths>
               <Include>
                 <ModulePath>.*Interactive.*</ModulePath>
+                <ModulePath>.*System.Linq.Async.dll$</ModulePath>
               </Include>
               <Exclude>
-                <ModulePath>.*Tests.*</ModulePath>
+                <ModulePath>.*Tests.dll$</ModulePath>
               </Exclude>
             </ModulePaths>