Revert "es_US causes all sorts of problems: it makes us think US's best lang is es."

This reverts commit 5d1cff4d5434e0fdcf88bf89e89a8a685adc0a67.

The plan is to notice that en_US is more populous than es_US and use
that fact, instead of relying on deleting files.

Auditors: james

Test plan:
None