fix: set array function name by array schema

[ivan-tymoshenko]

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

1. Set array context function by array schema instead of array's items schema.
2. There is no need to have two different Maps for storing context functions names.

[mcollina]

lgtm