[Rakudo] Cleaned up the use if isxxx() functions in Perl6Str PMC to pass the coding standards tests.
[Rakudo] Cleaned up the use if isxxx() functions in Perl6Str PMC to pass the
coding standards tests.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@26372 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

gagern/parrot,gitster/parrot,FROGGS/parrot,fernandobrito/parrot,fernandobrito/parrot,tkob/parrot,youprofit/parrot,tkob/parrot,parrot/parrot,FROGGS/parrot,tewk/parrot-select,tewk/parrot-select,fernandobrito/parrot,tkob/parrot,gagern/parrot,youprofit/parrot,tewk/parrot-select,gitster/parrot,gagern/parrot,tkob/parrot,parrot/parrot,parrot/parrot,gitster/parrot,youprofit/parrot,parrot/parrot,FROGGS/parrot,gitster/parrot,tewk/parrot-select,youprofit/parrot,tkob/parrot,fernandobrito/parrot,fernandobrito/parrot,tkob/parrot,fernandobrito/parrot,youprofit/parrot,tewk/parrot-select,tewk/parrot-select,gagern/parrot,fernandobrito/parrot,tkob/parrot,gagern/parrot,parrot/parrot,FROGGS/parrot,FROGGS/parrot,gagern/parrot,youprofit/parrot,tkob/parrot,FROGGS/parrot,youprofit/parrot,gitster/parrot,FROGGS/parrot,gagern/parrot,gitster/parrot,gitster/parrot,FROGGS/parrot,youprofit/parrot,tewk/parrot-select