* EVM gasCall values always stay on positive side This is also another part of preparations before converting GasInt to uint64 * Fix test_evm_support
* Reduce EVM complexity by removing forkOverride * Fixes
1. test_state_db and test_ledger -> test_ledger. They are the same thing now. 2. stack, memory, code_stream, gas_meter, misc, overflow -> test_evm_support. They are small tests and fall into the same area.