Create InsecureRandMoneyAmount() test util helper

to generate semi-random CAmounts up to MAX_MONEY rather
than only uint32, and use it in the unit tests.

src/test/validation_chainstate_tests.cpp

@@ -32,7 +32,7 @@ BOOST_AUTO_TEST_CASE(validation_chainstate_resize_caches)
         uint256 txid = InsecureRand256();
         COutPoint outp{txid, 0};
         newcoin.nHeight = 1;
-        newcoin.out.nValue = InsecureRand32();
+        newcoin.out.nValue = InsecureRandMoneyAmount();
         newcoin.out.scriptPubKey.assign(uint32_t{56}, 1);
         coins_view.AddCoin(outp, std::move(newcoin), false);