Add a debug print for a random failure

```
  1) Error:
TestRubyLiteral#test_float:
ArgumentError: SyntaxError#path changed: "(eval at /home/chkbuild/chkbuild/tmp/build/20240527T050036Z/ruby/test/ruby/test_literal.rb:642)"->"(eval at /home/chkbuild/chkbuild/tmp/build/20240527T050036Z/ruby/test/ruby/test_literal.rb:642)"
```
https://rubyci.s3.amazonaws.com/s390x/ruby-master/log/20240527T050036Z.fail.html.gz

Author: mame

test/ruby/test_literal.rb

@@ -640,6 +640,10 @@ def test_float
           end
           begin
             r2 = eval(s)
+          rescue ArgumentError
+            # Debug log for a random failure: ArgumentError: SyntaxError#path changed
+            $stderr.puts "TestRubyLiteral#test_float failed: %p" % s
+            raise
           rescue SyntaxError => e
             r2 = :err
           rescue NameError