[lldb][DataFormatter] Unwrap reference type when formatting std::unordered_map (#145872)

Desugar any potential references/typedefs before checking
`isStdTemplate`. Previously, the typename might've been:
```
const std::unordered_map<...> &
```
for references. This patch gets the pointee type before grabbing the
canonical type. `GetNonReferenceType` will unwrap typedefs too, so we
should always end up with a non-reference before we get to
`GetCanonicalType`.

https://github.com/llvm/llvm-project/issues/145847

lldb/source/Plugins/Language/CPlusPlus/LibCxxUnorderedMap.cpp

@@ -113,8 +113,10 @@ CompilerType lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
   // wraps a std::pair. Peel away the internal wrapper type - whose structure is
   // of no value to users, to expose the std::pair. This matches the structure
   // returned by the std::map synthetic provider.
-  if (isUnorderedMap(
-          m_backend.GetCompilerType().GetCanonicalType().GetTypeName())) {
+  if (isUnorderedMap(m_backend.GetCompilerType()
+                         .GetNonReferenceType()
+                         .GetCanonicalType()
+                         .GetTypeName())) {
     std::string name;
     CompilerType field_type =
         element_type.GetFieldAtIndex(0, name, nullptr, nullptr, nullptr);