This is primarily to cover the handling of localised digits,
which previously wasn't being tested, leading to T261706.
Bug: T261706
Change-Id: I9de7f01f77e767e9048c85604b559af4bca0de91
Expand the 'signatures-funny' test case with more examples, which
don't behave correctly.
Follow-up commits I04a8ea09401e06f2d4bb1f226f17eb528b29ed95 and
Ic26a87642f8a15d5de2f7073d4d8176b299c7f94 fix them.
Bug: T255738
Change-Id: I0fdd8bdf11b497ffeed37c37953c5730f6e4f3b7