Ruby: Update filename in test fixture

Author: hmac

ruby/ql/test/library-tests/frameworks/Core.expected

@@ -1,8 +1,8 @@
 subshellLiteralExecutions
-| Core.rb:1:1:1:10 | `echo foo` |
-| Core.rb:2:1:2:12 | `echo foo` |
-| Core.rb:3:1:3:12 | `echo foo` |
-| Core.rb:4:1:4:12 | `echo foo` |
-| Core.rb:5:1:5:12 | `echo foo` |
+| Stdlib.rb:1:1:1:10 | `echo foo` |
+| Stdlib.rb:2:1:2:12 | `echo foo` |
+| Stdlib.rb:3:1:3:12 | `echo foo` |
+| Stdlib.rb:4:1:4:12 | `echo foo` |
+| Stdlib.rb:5:1:5:12 | `echo foo` |
 subshellHeredocExecutions
-| Core.rb:7:1:7:7 | <<`EOF` |
+| Stdlib.rb:7:1:7:7 | <<`EOF` |