`assert` code block

The current way to perform static computation is by using `assert`. It's ugly and it's abusing its original intention.

```dart
assert(() {
// run static computation
return true;
}());
```

Why not simply borrow the syntax from C++?

```c++
static {
// run static computation
}
```

The issue compares Dart's current assert-based static computation with a proposed C++-style static block, but names no files, tests, or specification sections. Start by reviewing how static computation is currently defined in the Dart language specification and determine the syntax and semantics such a block would require. Done would require an accepted language-design decision and corresponding specification work.

Written by the indexing model from the issue text.