swift234

[swiftc] Add crash triggered in swift::DeclContext::isCascadingContextForLookup(bool) const. Bumps # of unresolved crash cases to 92.

Stack trace:

```
4  swift           0x00000000010c2e67 swift::DeclContext::isCascadingContextForLookup(bool) const + 7
5  swift           0x00000000010c2e87 swift::DeclContext::isCascadingContextForLookup(bool) const + 39
6  swift           0x00000000010c2e87 swift::DeclContext::isCascadingContextForLookup(bool) const + 39
9  swift           0x0000000000f0e6de swift::TypeChecker::resolveIdentifierType(swift::DeclContext*, swift::IdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 158
11 swift           0x0000000000f0f7b4 swift::TypeChecker::resolveType(swift::TypeRepr*, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 164
12 swift           0x0000000000f0e5d0 swift::TypeChecker::validateType(swift::TypeLoc&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 192
13 swift           0x0000000000eda0e2 swift::TypeChecker::checkGenericParamList(swift::ArchetypeBuilder*, swift::GenericParamList*, swift::GenericSignature*, bool, swift::GenericTypeResolver*) + 690
14 swift           0x0000000000edb6a7 swift::TypeChecker::validateGenericSignature(swift::GenericParamList*, swift::DeclContext*, swift::GenericSignature*, std::function<bool (swift::ArchetypeBuilder&)>, bool&) + 135
15 swift           0x0000000000edba46 swift::TypeChecker::validateGenericTypeSignature(swift::GenericTypeDecl*) + 102
16 swift           0x0000000000e9c90f swift::TypeChecker::validateDecl(swift::ValueDecl*, bool) + 367
20 swift           0x0000000000f0e6de swift::TypeChecker::resolveIdentifierType(swift::DeclContext*, swift::IdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 158
22 swift           0x0000000000f0f7b4 swift::TypeChecker::resolveType(swift::TypeRepr*, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 164
23 swift           0x0000000000f0e5d0 swift::TypeChecker::validateType(swift::TypeLoc&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) + 192
24 swift           0x0000000000ee1527 swift::TypeChecker::typeCheckPattern(swift::Pattern*, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*) + 967
29 swift           0x0000000000ea2156 swift::TypeChecker::typeCheckDecl(swift::Decl*, bool) + 150
32 swift           0x0000000000f0757a swift::TypeChecker::typeCheckFunctionBodyUntil(swift::FuncDecl*, swift::SourceLoc) + 346
33 swift           0x0000000000f073de swift::TypeChecker::typeCheckAbstractFunctionBodyUntil(swift::AbstractFunctionDecl*, swift::SourceLoc) + 46
34 swift           0x0000000000f07fa3 swift::TypeChecker::typeCheckAbstractFunctionBody(swift::AbstractFunctionDecl*) + 179
36 swift           0x0000000000ec4c11 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int) + 1281
37 swift           0x0000000000c594c9 swift::CompilerInstance::performSema() + 3289
39 swift           0x00000000007d7739 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2857
40 swift           0x00000000007a3748 main + 2872
Stack dump:
0.	Program arguments: /path/to/swift/bin/swift -frontend -c -primary-file validation-test/compiler_crashers/28315-swift-declcontext-iscascadingcontextforlookup.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -module-name main -o /tmp/28315-swift-declcontext-iscascadingcontextforlookup-e789e8.o
1.	While type-checking 'g' at validation-test/compiler_crashers/28315-swift-declcontext-iscascadingcontextforlookup.swift:31:1
2.	While type-checking 'b' at validation-test/compiler_crashers/28315-swift-declcontext-iscascadingcontextforlookup.swift:72:9
3.	While resolving type a at [validation-test/compiler_crashers/28315-swift-declcontext-iscascadingcontextforlookup.swift:152:5 - line:152:5] RangeText="a"
4.	While resolving type g at [validation-test/compiler_crashers/28315-swift-declcontext-iscascadingcontextforlookup.swift:157:15 - line:157:15] RangeText="g"
<unknown>:0: error: unable to execute command: Segmentation fault
<unknown>:0: error: compile command failed due to signal (use -v to see invocation)
```