refactor: use custom matcher for domain snapshot

[hi-ogawa]

Description

• follow up to feat(experimental): support aria snapshot #9668
  • diff hi-ogawa/vitest@feat-aria-snapshot...hi-ogawa:vitest:feat-custom-matcher-domain-snapshot

I'm thinking to use custom matcher mechanism for domain snapshot instead of exposing addDomainSnapshot, builtin toMatchDomainSnapshot etc.. Nothing should change for ARIA snapshot API surface, so putting this separate (as I don't want to block that one forever).

One blocker is integrating with vanilla expect.poll mechanism. We currently hard-code toMatchDomainSnapshot so that expect.poll will delegate retry logic to pollMatchDomain.

TODO

• allow expect.extend to specify options to let matchers to take over poll logic
• remove unneeded domain snapshot API surfaces
• docs

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[hi-ogawa]

This is merged via hi-ogawa#5