[nqp]:  Add tests for "repeat [while|until] <xblock>" form.
[nqp]:  Add tests for "repeat [while|until] <xblock>" form.

perl6/nqp-rx,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,perl6/nqp-rx,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp