Initialize the `random-seed` at emulator start-up

[pdarragh]

In the event that any randomized function is used (e.g., within a runtime function definition), it would probably be preferable for the randomization to be repeatable. Either standardize the seed at startup or else allow an argument to be passed to, e.g., asm-emulate to set the random seed (or just a toggle that will set the seed).

The standardized seed could be something based on the instructions, e.g., a hash of the formatted string of all the instructions or something. Or it could just be a fun integer.