[clang] Add support for builtin_verbose_trap (PR #79230)

[Akira Hatanaka via cfe-commits]

================
@@ -27,6 +27,9 @@ namespace llvm {
   }
 }
 
+// Prefix for __builtin_verbose_trap.
+#define CLANG_VERBOSE_TRAP_PREFIX "__llvm_verbose_trap"
----------------
ahatanak wrote:

@delcypher I don't think it has to mention `llvm`. Can we make it even shorter, e.g., `__trap_msg`?

https://github.com/llvm/llvm-project/pull/79230