Better alternative naming of RuntimeTransact?

[hackfisher]

          For the naming, I think runtime transact looks good for me because this indicates the source of this tx is from called from runtime to EVM executor, distinguishing it from ordinary evm transact using ecdsa unsigned extrinsic. Alternative naming would better to find a replacement for the runtime, `internal`, `system`, `private`?

Did we make test pass on the Pangolin yet?

Originally posted by @hackfisher in #1421 (review)