Usually? No they don't. They usually call them "non-ASCII characters" or "Unicode characters" - the latter being inaccurate because the ASCII characters are also in Unicode.

And even if people did usually call non-ASCII characters "international characters" it's still inaccurate and therefore not helpful, because "d" is both an ASCII and an international character. You can see how international it is by referring to a French, German, English, Spanish, Vietnamese, Polish etc dictionary.