Move upgrade tests to the new framework

[t0yv0]

This change makes tests consistent with the latest API exposed in github.com/pulumi/providertest/pulumitest and unblocks the upstream upgrade and release.

[github-actions]

Does the PR have any schema changes?

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

Maintainer note: consult the runbook for dealing with any breaking changes.

[github-actions]

Is README.md missing any configuration options?

assumeRoleWithWebIdentity not found in Configuration section
customCaBundle not found in Configuration section
defaultTags not found in Configuration section
ec2MetadataServiceEndpoint not found in Configuration section
ec2MetadataServiceEndpointMode not found in Configuration section
httpProxy not found in Configuration section
httpsProxy not found in Configuration section
ignoreTags not found in Configuration section
noProxy not found in Configuration section
retryMode not found in Configuration section
s3UsEast1RegionalEndpoint not found in Configuration section
sharedConfigFiles not found in Configuration section
skipRequestingAccountId not found in Configuration section
stsRegion not found in Configuration section
tokenBucketRateLimiterCapacity not found in Configuration section
useDualstackEndpoint not found in Configuration section

Please add a description for each of these options to README.md. Details about them can be found in either the upstream docs or schema.json.

[VenelinMartinov]

Is the default assert for all tests now "no replacements"? Non-blocking but it was previously "no changes" so it'd be nice to bring it back to that, otherwise we'd be losing coverage.

[t0yv0]

Yes. That's intentional. Testing for absence of updates is not a great default for us since it's totally fine with the users in most of the cases but creates friction that makes it difficult to iterate in this repository. I think we need to be looking at stricter checks when it is meaningful to some end user-scenario not here. They would be interesting to have in some kind of statistical/advisory role but the test suite right now is basically pass or fail there is no easy way to track e.g. warnings.