swift234

[swiftc] Add test case for crash triggered in swift::TypeChecker::checkGenericParamList(swift::ArchetypeBuilder*, swift::GenericParamList*, swift::GenericSignature*, bool, swift::GenericTypeResolver*)

Stack trace:

```
4  swift           0x0000000000ed9ded swift::TypeChecker::checkGenericParamList(swift::ArchetypeBuilder*, swift::GenericParamList*, swift::GenericSignature*, bool, swift::GenericTypeResolver*) + 93
6  swift           0x0000000000eda50e swift::TypeChecker::validateGenericFuncSignature(swift::AbstractFunctionDecl*) + 94
11 swift           0x0000000000ea2136 swift::TypeChecker::typeCheckDecl(swift::Decl*, bool) + 150
12 swift           0x0000000000ec4a92 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int) + 1026
13 swift           0x0000000000c58d09 swift::CompilerInstance::performSema() + 3289
15 swift           0x00000000007d735f swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2863
16 swift           0x00000000007a3378 main + 2872
Stack dump:
0.	Program arguments: /path/to/swift/bin/swift -frontend -c -primary-file validation-test/compiler_crashers/28307-swift-typechecker-resolveidentifiertype.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -module-name main -o /tmp/28307-swift-typechecker-resolveidentifiertype-687f0c.o
1.	While type-checking 'A' at validation-test/compiler_crashers/28307-swift-typechecker-resolveidentifiertype.swift:66:21
<unknown>:0: error: unable to execute command: Segmentation fault
<unknown>:0: error: compile command failed due to signal (use -v to see invocation)
```