fix(ivy): in ngcc, handle inline exports in commonjs code (#32129)

One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:

```typescript
import * as foo from './foo';

@NgModule({
  directives: [foo.DIRECTIVES],
})
```

In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.

When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.

```typescript
export const DIRECTIVES = [
  FooDir,
  BarDir,
];
```

can be downleveled to:

```javascript
exports.DIRECTIVES = [
  FooDir,
  BarDir,
```

Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.

To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.

PR Close #32129

packages/compiler-cli/src/ngtsc/reflection/test/ts_host_spec.ts

@@ -307,8 +307,9 @@ runInEachFileSystem(() => {
         } else if (directTargetDecl === null) {
           return fail('No declaration found for DirectTarget');
         }
-        expect(targetDecl.node.getSourceFile().fileName).toBe(_('/node_modules/absolute/index.ts'));
-        expect(ts.isClassDeclaration(targetDecl.node)).toBe(true);
+        expect(targetDecl.node !.getSourceFile().fileName)
+            .toBe(_('/node_modules/absolute/index.ts'));
+        expect(ts.isClassDeclaration(targetDecl.node !)).toBe(true);
         expect(directTargetDecl.viaModule).toBe('absolute');
         expect(directTargetDecl.node).toBe(targetDecl.node);
       });