swift234

[SourceKit] Add test case for crash triggered in swift::TypeChecker::typeCheckTopLevelCodeDecl(swift::TopLevelCodeDecl*)

Stack trace:

```
found code completion token A at offset 139
5  swift-ide-test  0x0000000000979936 swift::TypeChecker::typeCheckTopLevelCodeDecl(swift::TopLevelCodeDecl*) + 134
6  swift-ide-test  0x00000000009012cd swift::typeCheckTopLevelCodeDecl(swift::TopLevelCodeDecl*) + 1117
9  swift-ide-test  0x000000000085ce13 swift::performDelayedParsing(swift::DeclContext*, swift::PersistentParserState&, swift::CodeCompletionCallbacksFactory*) + 307
10 swift-ide-test  0x000000000076bb24 swift::CompilerInstance::performSema() + 3316
11 swift-ide-test  0x00000000007152b7 main + 33239
Stack dump:
0.	Program arguments: swift-ide-test -code-completion -code-completion-token=A -source-filename=<INPUT-FILE>
```