[Sol->Yul] assembly access to libraries unimplemented

Example code:
syntaxTests/inlineAssembly/assignment_from_library.sol
```
library L {
}

contract C {
function f() public pure {
assembly {
let x := L
}
}
}
```

Start with syntaxTests/inlineAssembly/assignment_from_library.sol and trace the Sol->Yul handling for the library reference shown there. Determine the expected behavior for assembly access to libraries, then add the implementation and verify that the syntax test passes.

Written by the indexing model from the issue text.