tests: Mark test coins_tests/updatecoins_simulation_test as non-deterministic #16221

Mark test coins_tests/updatecoins_simulation_test as non-deterministic:

$ contrib/devtools/test_deterministic_coverage.sh 1000
[2019-06-15 05:36:20] Measuring coverage, run [#1](/bitcoin-bitcoin/1/) of 1000
[2019-06-15 05:38:05] Measuring coverage, run [#2](/bitcoin-bitcoin/2/) of 1000
[2019-06-15 05:39:49] Measuring coverage, run [#3](/bitcoin-bitcoin/3/) of 1000
[2019-06-15 05:41:38] Measuring coverage, run [#4](/bitcoin-bitcoin/4/) of 1000
[2019-06-15 05:43:16] Measuring coverage, run [#5](/bitcoin-bitcoin/5/) of 1000
...
[2019-06-16 18:25:23] Measuring coverage, run [#880](/bitcoin-bitcoin/880/) of 1000
[2019-06-16 18:27:12] Measuring coverage, run [#881](/bitcoin-bitcoin/881/) of 1000
[2019-06-16 18:29:33] Measuring coverage, run [#882](/bitcoin-bitcoin/882/) of 1000
[2019-06-16 18:33:00] Measuring coverage, run [#883](/bitcoin-bitcoin/883/) of 1000
[2019-06-16 18:35:32] Measuring coverage, run [#884](/bitcoin-bitcoin/884/) of 1000

The line coverage is non-deterministic between runs. Exiting.

The test suite must be deterministic in the sense that the set of lines executed at least
once must be identical between runs. This is a necessary condition for meaningful
coverage measuring.

--- gcovr.run-1.txt     2019-06-15 05:38:05.282359029 +0200
+++ gcovr.run-884.txt   2019-06-16 18:37:23.518298374 +0200
@@ -269,7 +269,7 @@
 test/bloom_tests.cpp                         320     320   100%   
 test/bswap_tests.cpp                          13      13   100%   
 test/checkqueue_tests.cpp                    223     222    99%   169
-test/coins_tests.cpp                         478     472    98%   52,68,344-345,511,524
+test/coins_tests.cpp                         478     474    99%   52,68,511,524
 test/compilerbug_tests.cpp                    18      18   100%   
 test/compress_tests.cpp                       27      27   100%   
 test/crypto_tests.cpp                        268     268   100%   
@@ -401,5 +401,5 @@
 zmq/zmqpublishnotifier.h                       5       0     0%   12,31,37,43,49
 zmq/zmqrpc.cpp                                23       3    13%   16,18,20,23,33-35,37,40-47,51,62,64-65
 ------------------------------------------------------------------------------
-TOTAL                                      53323   28305    53%
+TOTAL                                      53323   28307    53%
 ------------------------------------------------------------------------------

I'd prefer to make it deterministic

@MarcoFalke Me too! Perhaps you are better at finding and fixing the root cause of the non-determinism in this case? I've been unsuccessful so far :-)

As with all suppressions this is just a stop-gap to make test_deterministic_coverage.sh usable for guarding against the introduction of new non-determinism until the source of non-determinism has been fixed.

I'm running contrib/devtools/test_deterministic_coverage.sh continuously against master on a testing server to find any introduction of new non-determinism in our tests: that's why I'm eager to get suppressions in for the remaining known cases. AFAIK, this one and #16212 are the only ones left.

They are not deterministic because SaltedOutpointHasher is not deterministic

...which uses GetRand(), so setting g_mock_deterministic_tests=true should make the test deterministic.

Oh, I forgot that I already added that mock flag in fae169c95e09ddf068dcaebc8170c4f41b02cf66.

Yeah, so should be trivial to make it deterministic. Closing this pull request.