C#: Remove clearsContent predicate from the framework code.

csharp/ql/lib/semmle/code/csharp/dataflow/internal/FlowSummaryImpl.qll

@@ -226,15 +226,6 @@ module Public {
       none()
     }
 
-    /**
-     * Holds if values stored inside `content` are cleared on objects passed as
-     * arguments at position `pos` to this callable.
-     *
-     * TODO: Remove once all languages support `WithoutContent` tokens.
-     */
-    pragma[nomagic]
-    predicate clearsContent(ParameterPosition pos, ContentSet content) { none() }
-
     /**
      * Holds if the summary is auto generated.
      */
@@ -328,23 +319,6 @@ module Private {
           SummaryComponentStack::singleton(TArgumentSummaryComponent(_))) and
       preservesValue = preservesValue1.booleanAnd(preservesValue2)
     )
-    or
-    exists(ParameterPosition ppos, ContentSet cs |
-      c.clearsContent(ppos, cs) and
-      input = SummaryComponentStack::push(SummaryComponent::withoutContent(cs), output) and
-      output = SummaryComponentStack::argument(ppos) and
-      preservesValue = true
-    )
-  }
-
-  private class MkClearStack extends RequiredSummaryComponentStack {
-    override predicate required(SummaryComponent head, SummaryComponentStack tail) {
-      exists(SummarizedCallable sc, ParameterPosition ppos, ContentSet cs |
-        sc.clearsContent(ppos, cs) and
-        head = SummaryComponent::withoutContent(cs) and
-        tail = SummaryComponentStack::argument(ppos)
-      )
-    }
   }
 
   /**
@@ -945,8 +919,7 @@ module Private {
         AccessPath inSpec, AccessPath outSpec, string kind
       ) {
         summaryElement(this, inSpec, outSpec, kind, true) and
-        not summaryElement(this, _, _, _, false) and
+        not summaryElement(this, _, _, _, false)
-        not this.clearsContent(_, _)
       }
 
       private predicate relevantSummaryElement(AccessPath inSpec, AccessPath outSpec, string kind) {