Fix unnecesary warning caused by using /x (RT#88189)

This fixes really annoying loud warnings like the following:

      t/03deu.t ......... Escape literal pattern white space under /x in regex; marked by <-- HERE in m/(|||||| <-- HERE ||||||||||||||||||||||||||| |¡|¢|£|¤|¥|¦|§|¨|©|ª|«|¬|­|®|¯|°|±|²|³|´|µ|¶|·|¸|¹|º
      |»|¼|½|¾|¿|À|Á|Â|Ã|Ä|Å|Æ|Ç|È|É|Ê|Ë|Ì|Í|Î|Ï|Ð|Ñ|Ò|Ó|Ô|Õ|Ö|×|Ø|Ù|Ú|Û|Ü|Ý|Þ|ß|à|á|â|ã|ä|å|æ|ç|è|é|ê|ë|ì|í|î|ï|ð|ñ|ò|ó|ô|õ|ö|÷|ø|ù|ú|û|ü|ý|þ|ÿ)/ at /home/frew/code/Test-utf8/lib/Test/utf8.pm line 184.
      Escape literal pattern white space under /x in regex; marked by <-- HERE in m/(||||||||||||||||||||||||||||||||| |¡|¢|£|¤|¥|¦|§|¨|©|ª|«|¬|­|®|¯|°|±|²|³|´|µ|¶|·|¸|¹|º|»|¼|½|¾|¿|À|Á|Â|Ã|Ä|Å <-- HER
      E |Æ|Ç|È|É|Ê|Ë|Ì|Í|Î|Ï|Ð|Ñ|Ò|Ó|Ô|Õ|Ö|×|Ø|Ù|Ú|Û|Ü|Ý|Þ|ß|à|á|â|ã|ä|å|æ|ç|è|é|ê|ë|ì|í|î|ï|ð|ñ|ò|ó|ô|õ|ö|÷|ø|ù|ú|û|ü|ý|þ|ÿ)/ at /home/frew/code/Test-utf8/lib/Test/utf8.pm line 184.