Match Nix loader errors in compiler spec

[bcardiff]

As part of NixOS/nixpkgs#195606 I noticed that the compiler loader specs fails on nix.

This PR tweaks, an already long regex, to accept one more case similar to #12323

output of compiler spec failure on nix

  1) Crystal::Loader .parse parses file paths
     Failure/Error: expect_raises(Crystal::Loader::LoadError, /#{Dir.current}\/foobar\.o.+(No such file or directory|image not found)|Cannot open "#{Dir.current}\/foobar\.o"/) do

       Expected Crystal::Loader::LoadError with message matching /\/private\/tmp\/nix-build-crystal-1.6.2.drv-0\/source\/foobar\.o.+(No such file or directory|image not found)|Cannot open "\/private\/tmp\/nix-build-crystal-1.6.2.drv-0\/source\/foobar\.o"/, got #<Crystal::Loader::LoadError: cannot load /private/tmp/nix-build-crystal-1.6.2.drv-0/source/foobar.o (dlopen(/private/tmp/nix-build-crystal-1.6.2.drv-0/source/foobar.o, 0x0009): tried: '/private/tmp/nix-build-crystal-1.6.2.drv-0/source/foobar.o' (no such file))
       Linker arguments: foobar.o
       Search path: > with backtrace:
         # src/compiler/crystal/loader/unix.cr:84:25 in 'load_file'
         # src/compiler/crystal/loader.cr:39:7 in 'new'
         # src/compiler/crystal/loader/unix.cr:60:7 in 'parse:search_paths'
         # spec/compiler/loader/unix_spec.cr:32:9 in '->'
         # src/spec/example.cr:45:13 in 'internal_run'
         # src/spec/example.cr:33:16 in 'run'
         # src/spec/context.cr:18:23 in 'internal_run'
         # src/spec/context.cr:339:7 in 'run'
         # src/spec/context.cr:18:23 in 'internal_run'
         # src/spec/context.cr:339:7 in 'run'
         # src/spec/context.cr:18:23 in 'internal_run'
         # src/spec/context.cr:156:7 in 'run'
         # src/spec/dsl.cr:220:7 in '->'
         # src/crystal/at_exit_handlers.cr:14:19 in 'run'
         # src/crystal/main.cr:50:14 in 'exit'
         # src/crystal/main.cr:45:5 in 'main'
         # src/crystal/main.cr:127:3 in 'main'

     # spec/compiler/loader/unix_spec.cr:31

[straight-shoota]

I'm wondering if we shouldn't simplify the spec a bit, instead of making it more complex for every new case we discover that doesn't match yet.

My idea would be to test that the error message contains the filename as well as either no such file or image not found (case-insensitive).

[straight-shoota]

It's fine to merge it as is, though.

[bcardiff]

Or even assert only the filename, I'm not sure we need the reason in this spec.