Asyncify update validators, SchemaType.prototype.doValidate(), save hooks for improved stack traces

[vkarpov15]

Summary

Stack traces for validate() are now fixed, and slightly better for save():

$ node gh-14250.js 
Save ValidationError: User validation failed: name: Validator failed for path `name` with value `A`
    at Document.invalidate (/home/v/Desktop/MongoDB/mongoose/lib/document.js:3327:32)
    at validatePath (/home/v/Desktop/MongoDB/mongoose/lib/document.js:3102:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Promise.all (index 0)
    at async model.$__validate (/home/v/Desktop/MongoDB/mongoose/lib/document.js:3043:3)
    at async model.validate (/home/v/Desktop/MongoDB/mongoose/lib/document.js:2645:5)
    at async model.validateBeforeSave (/home/v/Desktop/MongoDB/mongoose/lib/plugins/validateBeforeSave.js:34:7) {
  errors: {
    name: ValidatorError: Validator failed for path `name` with value `A`
        at SchemaString.doValidate (/home/v/Desktop/MongoDB/mongoose/lib/schemaType.js:1392:13)
        at validatePath (/home/v/Desktop/MongoDB/mongoose/lib/document.js:3094:24)
        at model.$__validate (/home/v/Desktop/MongoDB/mongoose/lib/document.js:3040:21)
        at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
        at async model.validate (/home/v/Desktop/MongoDB/mongoose/lib/document.js:2645:5)
        at async model.validateBeforeSave (/home/v/Desktop/MongoDB/mongoose/lib/plugins/validateBeforeSave.js:34:7) {
      properties: [Object],
      kind: 'user defined',
      path: 'name',
      value: 'A',
      reason: undefined,
      [Symbol(mongoose#validatorError)]: true
    }
  },
  _message: 'User validation failed'
}

Still need more work for save().

Examples

[hasezoey]

LGTM, just some questions to make sure.