Recursive anchors crash extension

[lemonyte]

Describe the bug

When using a recursive anchor, the extension outputs the following error and linting/validation stops working.

Request textDocument/foldingRange failed.
  Message: Request textDocument/foldingRange failed with message: Maximum call stack size exceeded
  Code: -32603

YAML:

# Arbitrary schema
# yaml-language-server: $schema=https://json.schemastore.org/github-action.json
&root
prop:
  sub: *root

The yaml package and Ajv have no problem parsing and applying the recursive anchor.

Output of YAML.parse():

<ref *1> { prop: { sub: [Circular *1] } }

Expected Behavior

Linting and validation should continue working.

Current Behavior

The extension crashes with the error indicated above.

Without recursive anchor, works as intended:

With recursive anchor, does not work:

Steps to Reproduce

1. Create a new YAML file
2. Paste the provided example content, and indicate an arbitrary schema to try validating the content
3. Remove the recursive *root reference, and notice that validation works as intended
4. Add the *root reference back, and notice that the extension stops working

Environment

• Windows
• Mac
• Linux
• other (please specify)

Notes

I may be able to open a PR fixing this if that becomes necessary.

If this issue should be under https://github.com/redhat-developer/yaml-language-server please transfer it.