Mapped types shouldn't transform any type

@ahejlsberg Can you remember #29793 and this? <!-- Please try to reproduce the issue with the latest published version. It may have already been fixed. For npm: `typescript@next` This is also the 'Nightly' version in the playground: http://www.typescriptlang.org/play/?ts=Nightly --> **TypeScript Version:** 3.7.x-dev.20200101 <!-- Search terms you tried before logging this (so others can find this issue more easily) --> **Search Terms:** **Code** ```ts type M<T> = { [P in keyof T]: T[P] }; type a = M<any>; ``` **Expected behavior:** Type a is `any`. **Actual behavior:** Type a is `{ [x: string]: any; }`. **Playground Link:** https://www.typescriptlang.org/play/index.html?ts=3.8.0-dev.20200101&ssl=1&ssc=1&pln=30&pc=1#code/C4TwDgpgBAsgPAFQHxQLxQN5QNoAUoCWAdlANYQgD2AZlAgLoBcde9UAvgNwBQokUAQzSw4AoiCScgA **Related Issues:** #29793