[NFC][clang] Fix static analyzer concerns

[Fznamznon]

Summary

InterpState frees resources in the destructor but doesn't
have user-written copy c'tor or assignment operator, so copying it using
default ones can cause double free.

[aaron.ballman]

LGTM!

clang/lib/AST/Interp/InterpState.h

 /// Interpreter context.
 class InterpState final : public State, public SourceMapper {
 public:
   InterpState(State &Parent, Program &P, InterpStack &Stk, Context &Ctx,
               SourceMapper *M = nullptr);
 
   ~InterpState();
 
+  InterpState(const InterpState &) = delete;
+  InterpState &operator=(const InterpState &) = delete;
+
   // Stack frame accessors.
   Frame *getSplitFrame() { return Parent.getCurrentFrame(); }
   Frame *getCurrentFrame() override;
   unsigned getCallStackDepth() override {
     return Current ? (Current->getDepth() + 1) : 1;
   }
   const Frame *getBottomFrame() const override {
     return Parent.getBottomFrame();