eDSL: Superior NameGen

[anshumanmohan]

The eDSL currently does a quick and dirty job when it comes to name generation.

It maintains a counter starting at 0, and every time it needs to makes a new name for a cell, it does something like {the_op_in_question}_{counter++}. This is why end up with things like reg_0, add_1, mult_2, etc.

The true solution is something akin to what Calyx itself does:

calyx/calyx-utils/src/namegenerator.rs

Lines 7 to 10 in 6f895a1

	pub struct NameGenerator {
	name_hash: HashMap<Id, i64>,
	generated_names: HashSet<Id>,
	}

It actually tracks existing names and avoids clashes. Let's eventually upgrade the eDSL to something like this.

Originally posted by @anshumanmohan in #2152 (comment)

[ethanuppal]

@rachitnigam, I'm curious why name_hash isn't used additionally to store whether the name has been defined, this task delegated to a separate HashSet? It doesn't seem hard to remove generated_names and keep the same functionality. That being said, it's not important.