Make sure we only execute END blocks once

Even if we call exit() inside an END block
.join can be argless, cleaning
Mention END block / exit fix
bump nqp/jvm rev for uniprop fix
bump nqp/moar rev for qw() and mmd fix
bump nqp rev for cclass warning
bump nqp rev for jvm build fix
Merge pull request #294 from sergot/nom

.join can be argless, cleaning
Bump NQP_REVISION, to get MoarVM OSR SEGV fix.
Test: make sure diag prints to standard error
Test: When diag'ing, don't precede blank lines with #
Test: diag about failed tests
Test: Report filename/line number of test failure
Test: Don't precede flunk messages with 'flunk'
Test: Make the program's exit status the # of tests failed

What about if this is > 255? or what if it's the sentinel value
for git bisect skip?
Test: Copy filehandles if we can

This way, a test can mess around with standard output/error
without screwing up tests
Test: Don't interleave diag and TAP output

Don't cross the streams!
Merge pull request #296 from hoelzro/test-better

Test better
Add LoL postcircumfix candidates

Though semilists don't work, so @a[0;1;0,1] is still NYI, the
functionality can at least be accessed via e.g. @a[LoL.new(0, 1, $(0, 1))]
Use new tests for S26