[clang] [clang-tools-extra] [libcxx] [lldb] [Clang] Make the SizeType, SignedSizeType and PtrdiffType be named sugar types instead of built-in types (PR #143653)

[Erich Keane via cfe-commits]

================
@@ -5613,3 +5613,16 @@ HLSLAttributedResourceType::findHandleTypeOnResource(const Type *RT) {
   }
   return nullptr;
 }
+
+StringRef PredefinedSugarType::getName(Kind KD) {
+  switch (KD) {
+  case Kind::SizeT:
+    return "__size_t";
+  case Kind::SignedSizeT:
+    return "__signed_size_t";
+  case Kind::PtrdiffT:
+    return "__ptrdiff_t";
+  case Kind::NumElements:;
----------------
erichkeane wrote:

```suggestion
  case Kind::NumElements:
  break;
```

https://github.com/llvm/llvm-project/pull/143653