TypeScript: Distinguish 'import {A} from "mod"' from 'import * as A from "mod"'

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For import {A} from "mod", we don't know if A is type-only (e.g. interface), runtime-only (e.g. variable), or type-and-runtime (e.g. class). For import * as A from "mod", we know that A is runtime-only. Give this distinction to the variable analyzer so it can make better diagnostics.