[lldb] Don't print to stderr in TypeSystemClang::GetBuiltinTypeForDWARFEncodingAndBitSize

[teemperor]

Summary

The current code just prints to the System's 'error log' which is usually stderr (+ some other log backend).
Printing to stderr however just interferes with LLDB's console UI, so when this code is triggered during
for example command completion it just breaks the LLDB console interface until the next redraw.

Instead just use the normal LLDB log which is by default hidden and is what users usually attach to
bug reports.

The only known bug that triggers this is https://bugs.llvm.org/show_bug.cgi?id=46775

[teemperor]

Still need to write a test.

[teemperor]

• Add some tests

[teemperor]

• Remove duplicated newline.

[labath]

I'm not sure how useful is that test case, but yeah....

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

default:
         if (type_name == "char32_t")
           return GetType(ast.Char32Ty);
         if (type_name == "char8_t")
           return GetType(ast.Char8Ty);
       }
     }
     break;
   }
-  // This assert should fire for anything that we don't catch above so we know
-  // to fix any issues we run into.
-  if (!type_name.empty()) {
-    std::string type_name_str = type_name.str();
-    Host::SystemLog(Host::eSystemLogError,
-                    "error: need to add support for DW_TAG_base_type '%s' "
-                    "encoded with DW_ATE = 0x%x, bit_size = %u\n",
-                    type_name_str.c_str(), dw_ate, bit_size);
-  } else {
-    Host::SystemLog(Host::eSystemLogError, "error: need to add support for "
-                                           "DW_TAG_base_type encoded with "
-                                           "DW_ATE = 0x%x, bit_size = %u\n",
-                    dw_ate, bit_size);
-  }
+
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES);
+  LLDB_LOG(log,
+           "error: need to add support for DW_TAG_base_type '{0}' "
+           "encoded with DW_ATE = {1:x}, bit_size = {2}",
+           type_name, dw_ate, bit_size);
   return CompilerType();
 }
 
 CompilerType TypeSystemClang::GetCStringType(bool is_const) {
   ASTContext &ast = getASTContext();
   QualType char_type(ast.CharTy);
 
   if (is_const)