https://dl.acm.org/doi/abs/10.1145/3363562
A Survey of Compiler Testing, Junjie Chen et al.
A few years ago I was working on a frontend for a compiler and was wondering how testing is done for things like these, so I was very delighted to see this paper. It is an overview of the research done on testing compilers. They looked at the various parts of testing (testcase generation, test oracles, processing results, etc.), but I really missed a section that would discuss what were they testing for. Based on their summaries of the papers, it seems that there were at least one that tested the parsers only, multiple that tried to make the compiler crash, some that looked for missed optimizations and some that was just verifying semantics. Other than this small issue, the paper is well organized, the summaries are short and easy to understand, and it looks like they did a really throughout job. It seems to be the perfect paper to read if you are considering testing some compilers.
Which you should, as they couldn't find any work about testing Scheme or Lisp compilers!