Testsuite: accept new output for T2507 and T8959a

Authored by thomie.

Description

Testsuite: accept new output for T2507 and T8959a

Unbreak the build.

Details

For the record this commit wasn't actually correct. The Unicode characters were being produced here due to the unicode terminal detection logic in DynFlags being broken by D898. This should be fixed by D1059.