Should non-native speakers get extra time to compose exam answers?
Disability conditions are applicable when there is an uncontrollable disadvantage that prevents the person fairly demonstrating their knowledge, skill and ability in the same timeframe.

This is not the case for a person who has and takes the option of moving to a country or region where their language proficiency is not sufficient to demonstrate knowledge or skill.

Such a person has the choice of developing their language skills to sufficiency or of simply studying at a university where the common language is one they are fluent in. They control the situation and therefore, it is their obligation to resolve it, not the assessor's duty.

Where these two groups intersect is a case rare enough that it should be handled on its own merits according to any applicable policy and law (which most likely will mean the extra time is given to account for the disability).