[Bitcode] Remove typed pointer abbreviation

[aeubanks]

Summary

Since typed pointers are deprecated.

[nikic]

LGTM

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

 void ModuleBitcodeWriter::writeTypeTable() {
   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 
   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
   SmallVector<uint64_t, 64> TypeVals;
 
   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 
-  // Abbrev for TYPE_CODE_POINTER.
-  auto Abbv = std::make_shared<BitCodeAbbrev>();
-  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
-  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
-  unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
-
   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
-  Abbv = std::make_shared<BitCodeAbbrev>();
+  auto Abbv = std::make_shared<BitCodeAbbrev>();
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
 
   // Abbrev for TYPE_CODE_FUNCTION.
   Abbv = std::make_shared<BitCodeAbbrev>();
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
case Type::PointerTyID: {
         TypeVals.push_back(AddressSpace);
         if (AddressSpace == 0)
           AbbrevToUse = OpaquePtrAbbrev;
       } else {
         // POINTER: [pointee type, address space]
         Code = bitc::TYPE_CODE_POINTER;
         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
         TypeVals.push_back(AddressSpace);
-        if (AddressSpace == 0)
-          AbbrevToUse = PtrAbbrev;
       }
       break;
     }
     case Type::FunctionTyID: {
       FunctionType *FT = cast<FunctionType>(T);
       // FUNCTION: [isvararg, retty, paramty x N]
       Code = bitc::TYPE_CODE_FUNCTION;
       TypeVals.push_back(FT->isVarArg());