Implement narrowType for InternalSchemaTypeExpression. It carries the same MatcherTypeSet as $type, but uses ElementPath with LeafArrayBehavior::kNoTraversal and NonLeafArrayBehavior::kTraverse.

The expression is generated from $jsonSchema but we can test it directly too.

{x: {$_internalSchemaType: number}} with x = any -> x is number
{x: {$not: {$_internalSchemaType: number}}} with x = any -> x is any except number
{x: {$_internalSchemaType: [number, string]}} with x = any -> x is number|string
{$jsonSchema: {required: ['a'], properties: {a: {bsonType: 'number', maximum: 10}}}} -> a is number