C#: Address review comments.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dataflow/FlowSummary.qll

@@ -159,7 +159,7 @@ private class RecordConstructorFlowRequiredSummaryComponentStack extends Require
     exists(Property p |
       recordConstructorFlow(_, _, p) and
       head = SummaryComponent::property(p) and
-      this = SummaryComponentStack::singleton(SummaryComponent::return())
+      this = SummaryComponentStack::return()
     )
   }
 

csharp/ql/lib/semmle/code/csharp/frameworks/system/Text.qll

@@ -29,8 +29,7 @@ class SystemTextStringBuilderClass extends SystemTextClass {
 /** Clear content for `System.Text.StringBuilder.Clear`. */
 private class SystemTextStringBuilderClearFlow extends SummarizedCallable {
   SystemTextStringBuilderClearFlow() {
-    this.getDeclaringType() instanceof SystemTextStringBuilderClass and
-    this.hasName("Clear")
+    this = any(SystemTextStringBuilderClass s).getAMethod("Clear")
   }
 
   override predicate clearsContent(ParameterPosition pos, DataFlow::Content content) {