[xlscc]two crashes in xlscc run, I attach the testcases

**Describe the bug**
One issue happen in runswitch diretory is that i want to use pipeline struct for switch.cc.Please run runswitch_pipeline.sh to reproduce the issue.
Another crash is in simple_loop directory.

**To Reproduce**
Steps to reproduce the behavior:
1.use runswitch_pipeline.sh to reproduce the first crash issue;
1.use runsimple_pipelined_loop.sh to reproduce the second issue;

**Environment (this can be helpful for troubleshooting):**
- OS: Ubuntu
- Versions 24.04
[xls_issues_20240406.tar.gz](https://github.com/google/xls/files/14897325/xls_issues_20240406.tar.gz)