Remove unnecessary Output.flushs before Global.exit and Global.crash

[wooster0]

I thought about this a bit more and realized that we could remove Global.exit's code parameter because in 99.5% of all cases we only ever exit with either 1 or 0, so we could actually make Global.crash() always exit with 1 (which it does already) and Global.exit() always exit with 0, indicating failure and success, respectively. We might also want to rename Global.crash to Global.fail because Global.crash can mislead people that it's only called when a bug is encountered. And we should explicitly mention in the docs of those two that they already flush output. This way we can prevent these mistakes in the future.
Or maybe we could only have one function that exits and we let it take an enum. So you can do Global.exit(.error) and Global.exit(.success). I think that might actually be the best and most readable solution.
In fact we could make it a union(enum) and allow exit(.{ .custom = 50 }); too for codes that are not 0 or 1.
Should I do the above in a followup PR?
This PR would be in preparation for that.

Additionally, the first commit fixes this issue I found:

$ bun run
No "scripts" in package.json found.$ 

(missing newline)

[wooster0]

Here's why it works:
https://github.com/Jarred-Sumner/bun/blob/main/src/__global.zig#L51
https://github.com/Jarred-Sumner/bun/blob/main/src/__global.zig#L124

[Jarred-Sumner]

Thank you

[wooster0]

@Jarred-Sumner thank you for merging.