[AST] Simplify Type::isSizelessBuiltinType(). NFC.

Reuse isSVESizelessBuiltinType() and isRVVSizelessBuiltinType().

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D156686

Author: tclin914

clang/lib/AST/Type.cpp

@@ -2353,14 +2353,11 @@ bool Type::isIncompleteType(NamedDecl **Def) const {
 }
 
 bool Type::isSizelessBuiltinType() const {
+  if (isSVESizelessBuiltinType() || isRVVSizelessBuiltinType())
+    return true;
+
   if (const BuiltinType *BT = getAs<BuiltinType>()) {
     switch (BT->getKind()) {
-      // SVE Types
-#define SVE_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
-#include "clang/Basic/AArch64SVEACLETypes.def"
-#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
-#include "clang/Basic/RISCVVTypes.def"
-      return true;
       // WebAssembly reference types
 #define WASM_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
 #include "clang/Basic/WebAssemblyReferenceTypes.def"