[lldb] Also disable de-registration of EHFrames in IRExecutionUnit

[teemperor]

Summary

We disabled registration by providing an empty registerEHFrames, so we should also provide an empty deregisterEHFrames
in case that function relies on registerEHFrames being called before. Currently deregisterEHFrames is a no-op anyway
as it just iterates over the (empty( list of registered EHFrames and then clear the empty list.

lldb/include/lldb/Expression/IRExecutionUnit.h

public:
     bool finalizeMemory(std::string *ErrMsg) override {
       // TODO: Ensure that the instruction cache is flushed because
       // relocations are updated by dy-load.  See:
       //   sys::Memory::InvalidateInstructionCache
       //   llvm::SectionMemoryManager
       return false;
     }
 
+    // Ignore any EHFrame registration.
     void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
                           size_t Size) override {}
+    void deregisterEHFrames() override {}
 
     uint64_t getSymbolAddress(const std::string &Name) override;
     
     // Find the address of the symbol Name.  If Name is a missing weak symbol
     // then missing_weak will be true.
     uint64_t GetSymbolAddressAndPresence(const std::string &Name, 
                                          bool &missing_weak);