The `NgModule` handler generates `R3References` for its declarations, imports,
exports, and bootstrap components, based on the relative import path
between the module and the classes it's referring to. This works fine for
compilation of a .ts Program inside ngtsc, but in ngcc the import needed
in the .d.ts file may be very different to the import needed between .js
files (for example, if the .js files are flattened and the .d.ts is not).
This commit introduces a new API in the `ReflectionHost` for extracting the
.d.ts version of a declaration, and makes use of it in the
`NgModuleDecorationHandler` to write a correct expression for the `NgModule`
definition type.
PR Close#26403
1918f8d5b5