Add a test for non-breaking space in Perl 6

[AlexDaniel]

See this: d8d26e2

Given that some tests are now optional, we can freely do stuff like this.

[gfldex]

Please keep in mind that some rancid What Ever Online (TM) used by Online "Journalists" may turn Perl 6 into Perl 6 in articles or even a heading. You may actually make the situation worse be being conservative while receiving and liberal while sending.

[coke]

This is now available in 'make xtest', as a failing test.

[coke]

Perl 6's take on unicode has always been to push the envelope and encourage others to improve their handling as well.

[AlexDaniel]

Anybody willing to work on making it pass?

[Altai-man]

@AlexDaniel, I already did it locally(just sed), but this test reacts not only to Perl 6, but to Perl 5. And, generally, Perl $any-digit. Do we want Perl 5 to be non-breakable too?
Ah, judging by test message, yes.