refactor: require() now uses exit codes starting from 1024

[Shvandre]

Issue

Closes #2245 .

[anton-trunov]

Add a test demonstrating

require(false, "second");
require(false, "second");

is handled correctly.

[anton-trunov]

One more thought: this PR breaks backwards compatibility with the current behavior of require: require(cond, "error message") in several places will have the same exit code because the string is shared.

[novusnota]

One more thought: this PR breaks backwards compatibility with the current behavior of require: require(cond, "error message") in several places will have the same exit code because the string is shared.

I think that's reasonable. For posterity though, I'll push the updated docs for require() in a moment since I've almost finished them :)

[anton-trunov]

I don't think we need one more source of implicitness in the language, especially the one that breaks backwards compatibility