[ABI] mangleCXXCtorVTable mangles an incorrect name

[tcwzxx]

namespace A {

class VBase {
 public:
  virtual ~VBase() {};
};

struct Wrap {};

template <typename T>
class Impl : public virtual VBase {
 public:
};

}  // namespace A

struct Inst : public A::Impl<A::Wrap> {};

void Test() { Inst a; }

The code above will generate a CtorVTable with the name _ZTC4Inst0_N1A4ImplINS_4WrapEEE. After demangling, the result is construction vtable for A::Impl<Inst::Wrap>-in-Inst. However, Inst::Wrap is incorrect.

llvm-project/clang/lib/AST/ItaniumMangle.cpp

Lines 7327 to 7338 in b0ffaa7

	void ItaniumMangleContextImpl::mangleCXXCtorVTable(const CXXRecordDecl *RD,
	int64_t Offset,
	const CXXRecordDecl *Type,
	raw_ostream &Out) {
	// <special-name> ::= TC <type> <offset number> _ <base type>
	CXXNameMangler Mangler(*this, Out);
	Mangler.getStream() << "_ZTC";
	Mangler.mangleNameOrStandardSubstitution(RD);
	Mangler.getStream() << Offset;
	Mangler.getStream() << '_';
	Mangler.mangleNameOrStandardSubstitution(Type);
	}

Because mangleNameOrStandardSubstitution never adds RD as a substitution.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: tcwzxx (tcwzxx)

```C++

namespace A {

class VBase {
public:
virtual ~VBase() {};
};

struct Wrap {};

template <typename T>
class Impl : public virtual VBase {
public:
};

} // namespace A

struct Inst : public A::Impl<A::Wrap> {};

void Test() { Inst a; }

The code above will generate a `CtorVTable` with the name `_ZTC4Inst0_N1A4ImplINS_4WrapEEE`. After demangling, the result is `construction vtable for A::Impl<Inst::Wrap>-in-Inst`. However, `Inst::Wrap` is incorrect.

https://github.com/llvm/llvm-project/blob/b0ffaa79050460d724eec1b12363c439b43d5ae5/clang/lib/AST/ItaniumMangle.cpp#L7327-L7338

 because `mangleNameOrStandardSubstitution` never adds `RD` as a substitution




</details>

[tcwzxx]

For CXXCtorVTable

<special-name> ::= TC <type> <offset number> _ <base type>

I think we should use mangleType instead of mangleNameOrStandardSubstitution.