This patch fixes `-Wreturn-type` warnings which happens if LLVM is built
with GCC compiler (14.1 is used for detecting)
Warnings:
```
llvm-project/lldb/source/ValueObject/DILLexer.cpp: In static member function ‘static llvm::StringRef lldb_private::dil::Token::GetTokenName(Kind)’:
llvm-project/lldb/source/ValueObject/DILLexer.cpp:33:1: warning: control reaches end of non-void function [-Wreturn-type]
33 | }
| ^
```
and:
```
llvm-project/lldb/source/DataFormatters/TypeSummary.cpp: In member function ‘virtual std::string lldb_private::TypeSummaryImpl::GetSummaryKindName()’:
llvm-project/lldb/source/DataFormatters/TypeSummary.cpp:62:1: warning: control reaches end of non-void function [-Wreturn-type]
62 | }
| ^
```
Technically, it is a bug in Clang (see #115345), however, UBSan with
Clang should detect these places, therefore it would be nice to provide
a return statement for all possible inputs (even invalid).
