[CodeComplete] Don't crash if solution doesn't contain a type for the parsed expression
[CodeComplete] Don't crash if solution doesn't contain a type for the parsed expression

In rdar://82027315 we are trying to retrieve the type of an `ASTNode` that doesn’t have a type associated with it in the solution from `getTypeForCompletion`.

This shouldn’t happen but we shouldn’t crash because of it, either. Since we already have handling logic for null types returned by `getTypeForCompletion` in place, I’m adding a check if the solution contains a type for the given node. If not, we’re causing an assertion failure and are returning a null type in non-assert builds.

roambotics/swift,apple/swift,glessard/swift,apple/swift,apple/swift,roambotics/swift,xwu/swift,benlangmuir/swift,xwu/swift,rudkx/swift,gregomni/swift,JGiola/swift,gregomni/swift,benlangmuir/swift,gregomni/swift,atrick/swift,roambotics/swift,ahoppen/swift,gregomni/swift,xwu/swift,glessard/swift,JGiola/swift,gregomni/swift,ahoppen/swift,benlangmuir/swift,rudkx/swift,glessard/swift,benlangmuir/swift,apple/swift,JGiola/swift,apple/swift,glessard/swift,benlangmuir/swift,xwu/swift,rudkx/swift,glessard/swift,ahoppen/swift,ahoppen/swift,JGiola/swift,gregomni/swift,xwu/swift,atrick/swift,xwu/swift,roambotics/swift,roambotics/swift,ahoppen/swift,atrick/swift,ahoppen/swift,rudkx/swift,apple/swift,atrick/swift,glessard/swift,atrick/swift,roambotics/swift,JGiola/swift,xwu/swift,JGiola/swift,benlangmuir/swift,atrick/swift,rudkx/swift,rudkx/swift