Tornado tests assume metric data_points implement Iterator

[lancetarn]

This is related to

• Sum/Histogram/Gauge.data_points annotated as Sequence but actual type is generator opentelemetry-python#3021
• Avoid generator in _ViewInstrumentMatch.collect() opentelemetry-python#3035

The SDK defines data_points as (at most) an Iterable, not an Iterator. The related PR will convert them to a Sequence, which matches a consumer's type definition and will avoid holding a lock in an unrealized generator.

Steps to reproduce
See https://github.com/open-telemetry/opentelemetry-python/actions/runs/3482444373/jobs/5842457813#step:7:8461

What is the expected behavior?
Tests should pass

What is the actual behavior?
Tests fail due to next call on unsupported type.