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/ngcc/test/host/esm2015_host_spec.ts

@@ -1538,8 +1538,9 @@ runInEachFileSystem(() => {
           'SomeClass',
         ]);
 
-        const values = Array.from(exportDeclarations !.values())
-                           .map(declaration => [declaration.node.getText(), declaration.viaModule]);
+        const values =
+            Array.from(exportDeclarations !.values())
+                .map(declaration => [declaration.node !.getText(), declaration.viaModule]);
         expect(values).toEqual([
           [`Directive: FnWithArg<(clazz: any) => any>`, null],
           [`a = 'a'`, null],