Always report rng seed from builtin reporters

Not all reporters use a format that supports this, so TeamCity
and Automake reporters still do not report it. The console
reporter now reports it even on successful runs, where before
it only reported the rng seed in the header, which was showed
either for failed run, or for run with `-s`.

CLoses #2065

tests/SelfTest/Baselines/tap.sw.approved.txt

@@ -1,3 +1,4 @@
+# rng-seed: 1
 # # A test name that starts with a #
 ok {test-number} - with 1 message: 'yay'
 # #1027: Bitfields can be captured