leaveNode(node) {
    this.currentNode = node;

    /*
     * Updates the code path.
     * And emits onCodePathStart/onCodePathSegmentStart events.
     */
    processCodePathToExit(this, node);

    // Emits the last onCodePathStart/onCodePathSegmentStart events.
    postprocess(this, node);

    this.currentNode = null;
  }
Does the process to leave a given AST node.
This updates state of analysis and calls `leaveNode` of the wrapped.
@param {ASTNode} node A node which is leaving.
@returns {void}