Integ: Test route53 target with api gateway domain name

[so0k]

ref: https://github.com/aws/aws-cdk/blob/f556fd18f789a8498f32298c07973e8aae4d3798/packages/@aws-cdk-testing/framework-integ/test/aws-route53-targets/test/integ.api-gateway-domain-name.ts