Tests failing on Ruby 3.3

[RDIL]

@hsbt after the release of 1.6.0 it seems there is still a segfault, but now it reproduces in this repo's tests: https://github.com/ruby/syck/actions/runs/28084164414/job/83145978245

[RDIL]

Does seem to be a different, unique issue though, not #50

/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_imemo_new+0x9c) [0x104ccbf54]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(lep_svar_set+0x7c) [0x104e64924]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_reg_search_set_match+0x1a8) [0x104d9fb20]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_reg_match+0x98) [0x104da1258]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(vm_call_cfunc_with_frame_+0xf0) [0x104e620f8]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(vm_exec_core+0x1dc0) [0x104e4787c]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_vm_exec+0x1ec) [0x104e4493c]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_funcallv+0x1e4) [0x104e4f3f4]
/Users/runner/hostedtoolcache/Ruby/3.3.11/arm64/lib/libruby.3.3.dylib(rb_funcall+0x84) [0x104e52aa4]

[hsbt]

@RDIL Did you see that segmentation fault with your environment? It's difficult to fix because that caused with CI environment.

Please file new issue when you have same failure with your environment.

[RDIL]

Sure, I'll try to reproduce locally.

[hsbt]

Thanks. I also try to reproduce my macOS M1 machine. But I could not see same issue with ASAN build.

[hsbt]

I added extra SEGV fixes at #61