This commit adds a documented test case for the segmentation fault that
occurs when using go/types.Scope.Insert() in llgo. The issue is caused
by a compiler bug in type metadata generation for stdlib packages.
The test case includes:
- Reproduction code (scope_insert.go)
- Detailed documentation (README.md) explaining the root cause
- Expected vs actual behavior
- Technical details for future developers
- Workarounds for users
This serves as a regression test that should pass once the compiler
bug in ssa/abitype.go is fixed.
Related: #642
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Co-authored-by: luoliwoshang <luoliwoshang@users.noreply.github.com>