TypeSize: remove unused deprecated methods

Forgotten in commit 547a507

Author: MaskRay

llvm/include/llvm/Support/TypeSize.h

@@ -328,10 +328,6 @@ class TypeSize : public details::FixedOrScalableQuantity<TypeSize, uint64_t> {
     return TypeSize(MinimumSize, true);
   }
 
-  constexpr ScalarTy getFixedSize() const { return getFixedValue(); }
-  
-  constexpr ScalarTy getKnownMinSize() const { return getKnownMinValue(); }
-
   // All code for this class below this point is needed because of the
   // temporary implicit conversion to uint64_t. The operator overloads are
   // needed because otherwise the conversion of the parent class