Don't call ECC_Start/ECC_Stop outside the test harness.

src/gtest/test_paymentdisclosure.cpp

@@ -208,6 +208,4 @@ TEST(paymentdisclosure, mainnet) {
 #if DUMP_DATABASE_TO_STDOUT == true
     mydb.DebugDumpAllStdout();
 #endif
-
-    ECC_Stop();
 }

src/gtest/test_transaction_builder.cpp

@@ -14,8 +14,6 @@ static const std::string tSecretRegtest = "cND2ZvtabDbJ1gucx9GWH6XT9kgTAqfb6cotP
 
 TEST(TransactionBuilder, Invoke)
 {
-    ECC_Start();
-
     SelectParams(CBaseChainParams::REGTEST);
     UpdateNetworkUpgradeParameters(Consensus::UPGRADE_OVERWINTER, Consensus::NetworkUpgrade::ALWAYS_ACTIVE);
     UpdateNetworkUpgradeParameters(Consensus::UPGRADE_SAPLING, Consensus::NetworkUpgrade::ALWAYS_ACTIVE);

src/wallet/gtest/test_wallet_zkeys.cpp

@@ -331,7 +331,5 @@ TEST(wallet_zkeys_tests, write_cryptedzkey_direct_to_db) {
     
     wallet2.GetSpendingKey(paymentAddress2, keyOut);
     ASSERT_EQ(paymentAddress2, keyOut.address());
-
-    ECC_Stop();
 }