Nearly everything in a merge of JS special assignments looks like a
valueDeclaration. This commit ensures that intermediate "module
declarations" are not used when a better valueDeclaration is available:
```js
// File1.js
var X = {}
X.Y.Z = class { }
// File2.js
X.Y = {}
```
In the above example, the `Y` in `X.Y.Z = class { }` was used as the
valueDeclaration for `Y` because it appeared before `X.Y = {}` in the
compilation.
This change exposed a bug in binding, #24703, that required a change in
typeFromPropertyAssignmentOutOfOrder. The test still fails for the
original reason it was created, and the new bug #24703 contains a repro.
