Fix the sort function for languages to have "strict weak ordering".

If you build libstdc++ with "debug" strictness, the test TestTypeLookup.py
will assert.  That's because we're calling llvm::sort (which redirects to
std::sort) with a function that doesn't obey strict weak ordering.

The error was that when the two languages were equal, we're sometimes
returning `true` but strict weak ordering requires that always be false.

This patch just makes the function behave properly.

Author: jimingham

lldb/source/Commands/CommandObjectType.cpp

@@ -2649,6 +2649,7 @@ class CommandObjectTypeLookup : public CommandObjectRaw {
                 return false;
               LanguageType lt1 = lang1->GetLanguageType();
               LanguageType lt2 = lang2->GetLanguageType();
+              if (lt1 == lt2) return false;
               if (lt1 == guessed_language)
                 return true; // make the selected frame's language come first
               if (lt2 == guessed_language)