Fix fuzzing problems

[pedrodesu]

These changes should make fuzzing pass. Such is the case in my machine, running for 2 minutes and through different runs. We will have more concrete results when we have this version running via cron for longer periods.

[pedrodesu]

Additionally, I'd like to take a moment here to talk about the naming of grow and try_grow: Does it make sense? From the name of the function, one would expect it to work the same as std's reserve I think. But instead of increasing the capacity by N, we set it to N. It's not what I would call a function with this behavior, personally. Feels like a misnomer. Some additional food for thought.

[alejandro-vaz]

what name are you suggesting then??

[pedrodesu]

How about something like set_min_capacity or reserve_total? I'm personally more of a fan of the former, but the latter seems more akin to what the user might expect (as std has reserve). Both show that it's an absolute operation and that we're always at best growing the vector (although the input is in absolute terms!), not shrinking.

[pedrodesu]

Additionally, is there a reason why we don't implement reserve and friends? And perhaps such other functions from Vec at that?

[alejandro-vaz]

yeah I'd say we should implement reserve and its derivatives, and some that may be useful in our code, though not in order to fill API gaps

I'd honestly go with the reserve variants instead of set just to make it somewhat relatable to Vec

[pedrodesu]

I agree. Anyway, this is a bit off-topic to this PR, so I'd suggest creating another issue for this matter. I believe the PR is good to go.