Looking at the SIL I came to the conclusion that `Unmanaged` ins fundamentally broken.
It's easier to directly bitcast between bridged and native SIL objects. It also produces simpler SIL which can be further optimized
Let's lldb's `po` command not print any "internal" properties of the conforming type.
This is useful if the `description` already contains all the information of a type instance.
For two reasons:
* We also like to check for assert failures in release builds. Although this could be achieved with `precondition`, it's easy to forget about it and use `assert` instead.
* We need to see the error message in crashlogs of release builds. This is even not the case for `precondition`.
Also, re-export the "Basic" module in "SIL" so that the new assert implementation is also available in the Optimizer module (where all files import SIL).
This fixes a dangling pointer issue when creating a `Swift.String` from `std::string`.
Also fixes a warning:
```
warning: variable 's' was never mutated; consider changing to 'let' constant
var s = SILBasicBlock_debugDescription(bridged)
~~~ ^
let
```
rdar://92963081
rdar://93053488
and introduce the StringRef struct.
It's more efficient.
Also, rename the `HasName` protocol to `HasShortDescription`, which introduces the new requirement `shortDescription`. This is need because `name` now has `StringRef` type and not `String` anymore
