Address review comments

rust/ql/lib/codeql/rust/controlflow/internal/ControlFlowGraphImpl.qll

@@ -374,9 +374,6 @@ class MatchExprTree extends PostOrderTree instanceof MatchExpr {
     or
     // Edge from the end of each arm to the match expression.
     last(super.getArm(_).getExpr(), pred, c) and succ = this and completionIsNormal(c)
-    or
-    // Edge from the end of last arm to the match expression.
-    last(super.getLastArm().getExpr(), pred, c) and succ = this and completionIsNormal(c)
   }
 }
 

rust/ql/lib/codeql/rust/controlflow/internal/SuccessorType.qll

@@ -34,7 +34,7 @@ abstract class ConditionalSuccessorImpl extends SuccessorTypeImpl {
   boolean value;
 
   bindingset[value]
-  ConditionalSuccessorImpl() { any() }
+  ConditionalSuccessorImpl() { exists(value) }
 
   /** Gets the Boolean value of this successor. */
   boolean getValue() { result = value }

rust/ql/lib/codeql/rust/elements/internal/MatchExprImpl.qll

@@ -41,11 +41,6 @@ module Impl {
     /**
      * Gets the number of arms of this match expression.
      */
-    int getNumberOfArms() { result = count(int i | exists(this.getArm(i))) }
-
-    /**
-     * Gets the last arm of this match expression.
-     */
-    MatchArm getLastArm() { result = this.getArm(this.getNumberOfArms() - 1) }
+    int getNumberOfArms() { result = this.getMatchArmList().getNumberOfArms() }
   }
 }