core/vm: move Log to core/types

This significantly reduces the dependency closure of ethclient, which no
longer depends on core/vm as of this change.

All uses of vm.Logs are replaced by []*types.Log. NewLog is gone too,
the constructor simply returned a literal.

core/blockchain_test.go

@@ -435,7 +435,7 @@ func (bproc) ValidateHeader(*types.Header, *types.Header, bool) error { return n
 func (bproc) ValidateState(block, parent *types.Block, state *state.StateDB, receipts types.Receipts, usedGas *big.Int) error {
 	return nil
 }
-func (bproc) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, vm.Logs, *big.Int, error) {
+func (bproc) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, *big.Int, error) {
 	return nil, nil, new(big.Int), nil
 }