[DebugInfo] Fix an assertion in DWARFTypePrinter (#178986)

A `DW_TAG_ptr_to_member_type` has no `RawName` and would trigger an
assertion.


7e48b14d1e/llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h (L497-L502)

The assertion is mostly benign since it will be compared with other
strings and return false.


7e48b14d1e/llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h (L505-L510)

But this is blocking our assertion builds.
We should escape `DW_TAG_ptr_to_member_type` as well when looking for
type names.

Adding a test to demonstrate how the assertion could be triggered, and
how we fixed it.

Depends on https://github.com/llvm/llvm-project/pull/180655

[Assisted-by](https://t.ly/Dkjjk): [Claude Opus
4.5](https://www.anthropic.com/news/claude-opus-4-5)

cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/Inputs/simplified_template_names.cpp

@@ -274,3 +274,12 @@ void f1() {
   t3<> v2;
 }
 } // namespace complex_type_units
+
+// Test for ptr_to_member_type in template value parameter
+namespace ptr_to_member_test {
+struct S {
+  int data_mem;
+};
+template <int S::*P> void f() {}
+void test() { f<&S::data_mem>(); }
+} // namespace ptr_to_member_test

llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h

@@ -495,7 +495,8 @@ bool DWARFTypePrinter<DieType>::appendTemplateParameters(DieType D,
       // symbol in the ELF symbol table to get back to the variable...
       // but probably not worth it.
       if (T.getTag() == dwarf::DW_TAG_pointer_type ||
-          T.getTag() == dwarf::DW_TAG_reference_type)
+          T.getTag() == dwarf::DW_TAG_reference_type ||
+          T.getTag() == dwarf::DW_TAG_ptr_to_member_type)
         continue;
       const char *RawName = detail::toString(T.find(dwarf::DW_AT_name));
       assert(RawName);