Add tests for Cairo 1 Dictionaries

[cicr99]

Refer to #146 (comment)

[quasilyte]

I can't find any example of dict usage that doesn't involve alloc in one form or another (now I see that it all boils down to the cairo0 segment allocation hint, this connection wasn't that clear before).

The only way to test the dicts right now is to use hints along with their runner directly. This could work with some operations that have simpler semantics. Since I'm still trying to find what contexts involve things like ShouldSkipSquashLoop and ShouldContinueSquashLoop (it's just an example), I can only write a biased test that more or less duplicates the code logic (we write at [ap+x], we read at [ap+x] inside a test and make an assertion). These kinds of tests feel redundant.

If we had a way to write a cairo0 integration-style test file, then we could test that dictionaries work as expected. These tests are expected to make Cairo compiler to emit all relevant dict-related hints for the code.

Or maybe I'm missing some context.