Fix parsing of type declaration edge case

[rtsao]

type
Foo = {}

// should be transformed to:

type;
Foo = {};

• https://www.typescriptlang.org/play?ts=4.0.2#code/C4TwDgpgUAYg9nABAXkQbwL5SA
• https://github.com/microsoft/TypeScript/blob/ee5f51bc0fc06964f2ba27217b5555a82a398673/tests/baselines/reference/asiPreventsParsingAsTypeAlias01.js
• https://github.com/microsoft/TypeScript/blob/ee5f51bc0fc06964f2ba27217b5555a82a398673/tests/baselines/reference/asiPreventsParsingAsTypeAlias02.js

[evanw]

Good catch! Thanks for the fix, and for adding test coverage.