C#: Address review comments.

csharp/ql/src/semmle/code/csharp/Stmt.qll

@@ -225,7 +225,9 @@ private module SwithStmtInternal {
   /** Implicitly reorder case statements to put the default case last if needed. */
   private predicate caseIndex(SwitchStmt ss, CaseStmt case, int index) {
     exists(int i | case = ss.getChildStmt(i) |
-      if case instanceof DefaultCase then index = 1000000 else index = i
+      if case instanceof DefaultCase
+      then index = max(int j | exists(ss.getChildStmt(j))) + 1
+      else index = i
     )
   }
 

csharp/ql/src/semmle/code/csharp/controlflow/ControlFlowGraph.qll

@@ -741,7 +741,6 @@ module ControlFlow {
         TLastRecBooleanNegationCompletion() or
         TLastRecNonBooleanCompletion() or
         TLastRecBreakCompletion() or
-        TLastRecNonBreakCompletion() or
         TLastRecSwitchAbnormalCompletion() or
         TLastRecInvalidOperationException() or
         TLastRecNonContinueCompletion() or
@@ -1150,10 +1149,6 @@ module ControlFlow {
           c0 instanceof BreakCompletion and
           c instanceof BreakNormalCompletion
           or
-          rec = TLastRecNonBreakCompletion() and
-          not c0 instanceof BreakCompletion and
-          c = c0
-          or
           rec = TLastRecSwitchAbnormalCompletion() and
           not c instanceof BreakCompletion and
           not c instanceof NormalCompletion and