jl_sigint_safepoint() causes segfault if run too early #39006
Description
I'm not entirely sure what the purpose of jl_sigint_safepoint() segfaulting is, but if run too early (because, for instance, jl_init() fails and tries to print something out to stdout, which in turn calls jl_uv_puts() which calls JL_SIGATOMIC_END()) it can cause an actual segfault. I think we may need to either prevent that segfault from being raised if we are not initialized enough to handle it, or we need to avoid calling things like jl_uv_puts() until we're more initialized.
This is important as useful error messages are getting lost while trying to be spat out, due to the segfault occuring after the first ERROR: gets printed out.