Introduce VTAny as isOverloaded = true. ValueType.isOverloaded` is used for;
- Define iPTRAny, vAny, fAny, and Any
 - Reflect ValueType.isOverloaded to LLVMType.isAny in Intrinsics.td
 - Reflect the condition to MVT::isOverloaded()
 
Introduce some fields in ValueType
- LLVMName
 - isInteger
 - isFP
 - isVector
 - isScalable
 - nElem
 - ElementType
 
Introduce VTVec<int nelem, ValueType elt, int value> to represent
the element type. VTVec.Size may be calculated by !mul(nelem, elt.Size).
Introduce list<ValueType> ValueTypes as convention for lookup.
Depends on D146906
I didn't know tablegen had assertions