swift234

[SIL] Add test case for crash triggered in swift::Parser::parseSILScope()

Stack trace:

```
sil-opt: /path/to/swift/include/swift/Parse/Parser.h:412: swift::SourceLoc swift::Parser::consumeToken(swift::tok): Assertion `Tok.is(K) && "Consuming wrong token kind"' failed.
8  sil-opt         0x0000000000a62cae swift::Parser::parseSILScope() + 2478
9  sil-opt         0x0000000000a9835b swift::Parser::parseTopLevel() + 827
10 sil-opt         0x0000000000a51170 swift::parseIntoSourceFile(swift::SourceFile&, unsigned int, bool*, swift::SILParserState*, swift::PersistentParserState*, swift::DelayedParsingCallbacks*) + 208
11 sil-opt         0x00000000007726c6 swift::CompilerInstance::performSema() + 3254
12 sil-opt         0x000000000075bb9d main + 1805
Stack dump:
0.	Program arguments: sil-opt -enable-sil-verify-all
1.	With parser at source location: <stdin>:3:12
```