dillon1000/react

Don't set the first option as selected in select tag with `size` attribute (#14242)

* Set 'size' attribute to select tag if it occurs before appending options

* Add comment about why size is assigned on select create. Tests

I added some more clarification for why size must be set on select
element creation:

- In the source code
- In the DOM test fixture
- In a unit test

* Use let, not const in select tag stub assignment