test: Implement unit tests for CWallet::CreateTransaction (#3667)
test: Implement unit tests for CWallet::CreateTransaction (#3667)

* test: Implement unit tests for CWallet::CreateTransaction

* test: Reset minRelayTxFee in CreateTransactionTest

At this point its modified from an other test when running all unit 
tests which lets this test fail unexpectedly.

* test: Lock cs_main/cs_wallet when required in CreateTransactionTest

* test: Add new test in CreateTransactionTest

Test if the wallet creation fails properly with the correct error
messages.

* test: Fixed expected test results for some CreateTransactionTest cases

* test: Fail if CreateTransaction runs into "Exceed max tries" case

* test: Adjust last return in CreateTransaction

* test: Drop dust tests
thelazier/dash,thelazier/dash,UdjinM6/dash,dashpay/dash,dashpay/dash,thelazier/dash,UdjinM6/dash,UdjinM6/dash,thelazier/dash,UdjinM6/dash,UdjinM6/dash,thelazier/dash,dashpay/dash,dashpay/dash,dashpay/dash