[poincare] TreeNode: delete useless method isChildRemovalTolerant

poincare/include/poincare/horizontal_layout_node.h

@@ -32,7 +32,6 @@ public:
   // TreeNode
   size_t size() const override { return sizeof(HorizontalLayoutNode); }
   int numberOfChildren() const override { return m_numberOfChildren; }
-  bool isChildRemovalTolerant() const override { return true; }
   void incrementNumberOfChildren(int increment = 1) override { m_numberOfChildren+= increment; }
   void decrementNumberOfChildren(int decrement = 1) override {
     assert(m_numberOfChildren >= decrement);

poincare/include/poincare/n_ary_expression_node.h

@@ -9,7 +9,6 @@ class NAryExpressionNode : public ExpressionNode { // TODO: VariableArityExpress
 public:
   //Tree
   int numberOfChildren() const override { return m_numberOfChildren; }
-  bool isChildRemovalTolerant() const override { return true; }
   void incrementNumberOfChildren(int increment = 1) { m_numberOfChildren+= increment; }
   void decrementNumberOfChildren(int decrement = 1) {
     assert(m_numberOfChildren >= decrement);

poincare/include/poincare/tree_by_reference.h

@@ -36,7 +36,6 @@ public:
 
   bool isDefined() const { return m_identifier != TreePool::NoNodeIdentifier && node() != nullptr; }
   bool isAllocationFailure() const { return isDefined() && node()->isAllocationFailure(); }
-  bool isChildRemovalTolerant() const { return isDefined() && node()->isChildRemovalTolerant(); }
 
   int nodeRetainCount() const {
     assert(isDefined());

poincare/include/poincare/tree_node.h

@@ -25,7 +25,6 @@ public:
   bool isStatic() const;
   virtual size_t size() const = 0;
   int identifier() const { return m_identifier; }
-  virtual bool isChildRemovalTolerant() const { return false; }
   int retainCount() const { return m_referenceCounter; }
   void setReferenceCounter(int refCount) { //TODO make this method privte with only friends that can access it
     if (isStatic()) {