swift234

Add crash type annotations and Valgrind output for memory errors.

Valgrind output:

```
$ valgrind swift -frontend -c validation-test/compiler_crashers/16694-swift-constraints-constraintsystem-opentype.swift
Invalid read of size 4
   at 0x1016C00: swift::TypeBase::getDesugaredType() (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/24394-swift-typevariabletype-implementation-getrepresentative.swift
Invalid read of size 8
   at 0x10121C4: swift::TypeBase::getCanonicalType() (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/25458-swift-archetypetype-getnestedtype.swift
Invalid read of size 8
   at 0xE52866: (anonymous namespace)::ConformanceChecker::recordTypeWitness(swift::AssociatedTypeDecl*, swift::Type, swift::TypeDecl*, swift::DeclContext*, bool, bool) (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/27203-swift-typeloc-iserror.swift
Invalid read of size 4
   at 0xE42CD5: swift::TypeChecker::checkConformance(swift::NormalProtocolConformance*) (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/27443-matchwitness.swift
Invalid read of size 8
   at 0xE4BAD1: checkMutating(swift::FuncDecl*, swift::FuncDecl*, swift::ValueDecl*) (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/27754-swift-typechecker-resolvetypeincontext.swift
Invalid read of size 8
   at 0x10121C4: swift::TypeBase::getCanonicalType() (in /path/to/swift/bin/swift)

$ valgrind swift -frontend -c validation-test/compiler_crashers/28155-swift-typechecker-validategenericfuncsignature.swift
Invalid read of size 2
   at 0xF35D76: swift::FunctionType::get(swift::Type, swift::Type, swift::AnyFunctionType::ExtInfo const&) (in /path/to/swift/bin/swift)
```