Comment 8 for bug 1915640

Another, shorter sequence:
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g++ -std=c++20 -fmodules-ts -x c++-system-header new
g++ -std=c++20 -fmodules-ts -x c++-system-header initializer_list
g++ -std=c++20 -fmodules-ts -x c++-system-header typeinfo
g++ -std=c++20 -fmodules-ts -x c++-system-header type_traits
g++ -std=c++20 -fmodules-ts -x c++-system-header exception
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/usr/local/include/c++/11.0.0/exception: internal compiler error: in write_cluster, at cp/module.cc:14600
0x6e2d56 module_state::write_cluster(elf_out*, depset**, unsigned int, depset::hash&, unsigned int*, unsigned int*)
 ../../gcc/gcc/cp/module.cc:14600
0xa62be8 module_state::write(elf_out*, cpp_reader*)
 ../../gcc/gcc/cp/module.cc:17734
0xa638fc finish_module_processing(cpp_reader*)
 ../../gcc/gcc/cp/module.cc:19860
0x9f72cb c_parse_final_cleanups()
 ../../gcc/gcc/cp/decl2.c:5175