`CodeCompletioString::getName()` was used only as the sorting keys in
`CodeCompletionContext::sortCompletionResults()` which is effectively
deprecated. There's no reason to check them in `swift-ide-test`. Instead,
check `printCodeCompletionResultFilterName()` that is actually used for
filtering.
This fixes code completion hitting llvm_unreachable("non-canonical or
unchecked type") in subst on a type containing an UnresolvedType.
Resolves rdar://problem/56726715
