Import fix for `export =`

TypeScript Version: 3.0.0-dev.20180621

Code

/// <reference path="fourslash.ts" />

// @Filename: /a.d.ts
////declare function a(): void;
////export = a;

// @Filename: /b.ts
////a;

goTo.file("/b.ts");
verify.importFixAtPosition(["?"]);

Expected behavior:

Get an import fix.

Actual behavior:

No fix. getAllReExportingModules doesn't handle this case.