[IR] Remove a couple explicitly deleted default constructors on classes that have a non-default constructor. NFC

The non-default constructor will implicitly delete the default constructor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305311 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/Constants.h

@@ -68,7 +68,6 @@ protected:
   void *operator new(size_t s) { return User::operator new(s, 0); }
 
 public:
-  ConstantData() = delete;
   ConstantData(const ConstantData &) = delete;
 
   /// Methods to support type inquiry through isa, cast, and dyn_cast.

include/llvm/IR/InstrTypes.h

@@ -903,8 +903,6 @@ protected:
           BasicBlock *InsertAtEnd);
 
 public:
-  CmpInst() = delete;
-
   // allocate space for exactly two operands
   void *operator new(size_t s) {
     return User::operator new(s, 2);