Country field should display the "- Select -" option to match core behavior

I am going with #56 which appears to work for my requirements (replacing a basic country selection with an Address field that only captures Country & Administrative Area). Not sure why anything other than "- Select -" would be a better placeholder so not applying #57 myself.

Thanks for the work!

Moving to 2.0.x-dev, as we've closed 8.x-1.x for any risky changes, and this one definitely counts (as evidenced by #45).

Also, bumping the status back to "needs review". Both #45 and #51 indicate that the patch needs further work (or at least exploration).

At a glance I can definitely say that we must not modify the address element like this:

diff --git a/src/Element/Address.php b/src/Element/Address.php
index b8df3be..f6a55c5 100644
--- a/src/Element/Address.php
+++ b/src/Element/Address.php
@@ -118,9 +118,7 @@ class Address extends FormElement {
     // Preselect the default country to ensure it's present in the value.
     $element['#default_value'] = (array) $element['#default_value'];
     $element['#default_value'] = self::applyDefaults($element['#default_value']);
-    if (empty($element['#default_value']['country_code']) && $element['#required']) {
-      $element['#default_value']['country_code'] = Country::getDefaultCountry($element['#available_countries']);
-    }
+

This is the big BC break that is breaking Commerce tests.

For this patch to be committable, it needs to limit itself to the country element/field only, leaving the address UX unchanged.

Re-roll of the patch on the 2.x branch as starting point